Perl 6 Documentationclass NumStr
Dual value floating-point number and string
is Num is Str
The dual value types (often referred to as allomorphs) allow for the representation of a value as both a string and a numeric type. Typically they will be created for you when the context is "stringy" but they can be determined to be numbers, such as in some quoting constructs:
my = <42.1e0>; say .^name; # OUTPUT: «NumStr»
As a subclass of both Num and Str, a NumStr will be accepted where either is expected. However, NumStr does not share object identity with Num- or Str-only variants:
my = <42e10>;my Num = ; # OK!my Str = ; # OK!say 42e10 ∈ <42e10 55 1>; # False; ∈ operator cares about object identity
Methods
method new
method new(Num , Str )
The constructor requires both the Num and the Str value, when constructing one directly the values can be whatever is required:
my = NumStr.new(42.1e0, "forty two and a bit");say +; # OUTPUT: «42.1»say ~; # OUTPUT: «"forty two and a bit"»
method Bool
Defined as:
multi method Bool(NumStr: --> Bool)
This method may be provided by the parent classes and not implemented in NumStr directly.
Returns False if the invocant is numerically ±0e0, otherwise returns True. String portion is not considered.
method Num
method Num
Returns the Num value of the NumStr.
method Numeric
Defined as:
multi method Numeric(NumStr: --> Num)multi method Numeric(NumStr: --> Num)
The :D variant returns the numeric portion of the invocant. The :U variant issues a warning about using an uninitialized value in numeric context and then returns value 0e0.
method Real
Defined as:
multi method Real(NumStr: --> Num)multi method Real(NumStr: --> Num)
The :D variant returns the numeric portion of the invocant. The :U variant issues a warning about using an uninitialized value in numeric context and then returns value 0e0.
method Str
Returns the string value of the NumStr.
method ACCEPTS
Defined as:
multi method ACCEPTS(NumStr: Any )
If $value is Numeric (including another allomorph), checks if invocant's Numeric part ACCEPTS the $value. If $value is Str, checks if invocant's Str part ACCEPTS the $value. If value is anything else, checks if both Numeric and Str parts ACCEPTS the $value.
say <5e0> ~~ "5.0"; # OUTPUT: «False»say <5e0> ~~ 5.0 ; # OUTPUT: «True»say <5e0> ~~ <5.0>; # OUTPUT: «True»
Operators
infix cmp
multi sub infix:<cmp>(NumStr , NumStr )
Compare two NumStr objects. The comparison is done on the Num value first and then on the Str value. If you want to compare in a different order then you would coerce to a Num or Str value first:
my = NumStr.new(42.1e0, "smaller");my = NumStr.new(43.1e0, "larger");say cmp ; # OUTPUT: «Less»say .Str cmp .Str; # OUTPUT: «More»
Type Graph
NumStr
Routines supplied by class Num
NumStr inherits from class Num, which provides the following routines:
(Num) method rand
method rand(Num: --> Num)
Returns a pseudo random number between 0 and the invocant.
(Num) sub srand
sub srand(Int --> Int)
Seeds the pseudo random number generator used by Num.rand with the provided value. Note that srand is called with a platform dependent value when a Perl 6 program is started.
(Num) method Capture
Defined as:
method Capture()
Throws X::Cannot::Capture.
Routines supplied by class Str
NumStr inherits from class Str, which provides the following routines:
(Str) routine chop
multi method chop(Str:)multi method chop(Str: Int() )
Returns the string with $chopping characters removed from the end.
say "Whateverable".chop(3.6); # OUTPUT: «Whatevera»my = "Whateverable";say .chop("3"); # OUTPUT: «Whatevera»
The $chopping positional is converted to Int before being applied to the string.
(Str) routine chomp
Defined as:
multi sub chomp(Str --> Str)multi method chomp(Str: --> Str)
Returns the string with a logical newline (any codepoint that has the NEWLINE property) removed from the end.
Examples:
say chomp("abc\n"); # OUTPUT: «abc»say "def\r\n".chomp; # OUTPUT: «def» NOTE: \r\n is a single grapheme!say "foo\r".chomp; # OUTPUT: «foo»
(Str) method contains
Defined as:
multi method contains(Str: Cool --> Bool)multi method contains(Str: Str --> Bool)multi method contains(Str: Cool , Int(Cool) --> Bool)multi method contains(Str: Str , Int --> Bool)
Coerces the invocant (represented in the signature by Str:D:, that would be the haystack) and first argument (which we are calling $needle) to Str (if it's not already, that is, in the first and third multi forms), and searches for $needle in the invocant (or haystack) starting from $pos characters into the string, if that is included as an argument. Returns True if $needle is found. $pos is an optional parameter, and if it's not present, contains will search from the beginning of the string (using the first two forms of the multi).
say <Hello, World>.contains('Hello', 0); # OUTPUT: «True»say "Hello, World".contains('Hello'); # OUTPUT: «True»say "Hello, World".contains('hello'); # OUTPUT: «False»say "Hello, World".contains('Hello', 1); # OUTPUT: «False»say "Hello, World".contains(','); # OUTPUT: «True»say "Hello, World".contains(',', 3); # OUTPUT: «True»say "Hello, World".contains(',', 10); # OUTPUT: «False»
In the first example, coercion is used to convert a List to a Str. In the 4th case, the 'Hello' string is not found since we have started looking at the second position in it (index 1). Note that because of how a List or Array is coerced into a Str, the results may sometimes be surprising. See traps.
(Str) routine lc
Defined as:
multi sub lc(Str --> Str)multi method lc(Str: --> Str)
Returns a lower-case version of the string.
Examples:
lc("A"); # RESULT: «"a"»"A".lc; # RESULT: «"a"»
(Str) routine uc
multi sub uc(Str --> Str)multi method uc(Str: --> Str)
Returns an uppercase version of the string.
(Str) routine fc
multi sub fc(Str --> Str)multi method fc(Str: --> Str)
Does a Unicode "fold case" operation suitable for doing caseless string comparisons. (In general, the returned string is unlikely to be useful for any purpose other than comparison.)
(Str) routine tc
multi sub tc(Str --> Str)multi method tc(Str: --> Str)
Does a Unicode "titlecase" operation, that is changes the first character in the string to title case, or to upper case if the character has no title case mapping
(Str) routine tclc
multi sub tclc(Str --> Str)multi method tclc(Str: --> Str)
Turns the first character to title case, and all other characters to lower case
(Str) routine wordcase
multi sub wordcase(Cool --> Str)multi sub wordcase(Str --> Str)multi method wordcase(Str: : = , Mu : = True --> Str)
Returns a string in which &filter has been applied to all the words that match $where. By default, this means that the first letter of every word is capitalized, and all the other letters lowercased.
(Str) method unival
multi method unival(Str --> Numeric)
Returns the numeric value that the first codepoint in the invocant represents, or NaN if it's not numeric.
say '4'.unival; # OUTPUT: «4»say '¾'.unival; # OUTPUT: «0.75»say 'a'.unival; # OUTPUT: «NaN»
(Str) method univals
multi method univals(Str --> List)
Returns a list of numeric values represented by each codepoint in the invocant string, and NaN for non-numeric characters.
say "4a¾".univals; # OUTPUT: «(4 NaN 0.75)»
(Str) routine chars
multi sub chars(Cool --> Int)multi sub chars(Str --> Int)multi sub chars(str --> int)multi method chars(Str: --> Int)
Returns the number of characters in the string in graphemes. On the JVM, this currently erroneously returns the number of codepoints instead.
(Str) method encode
multi method encode(Str = 'utf8', :, Bool() : = False, :)
Returns a Blob which represents the original string in the given encoding and normal form. The actual return type is as specific as possible, so $str.encode('UTF-8') returns a utf8 object, $str.encode('ISO-8859-1') a buf8. If :translate-nl is set to True, it will translate newlines from \n to \n\r, but only in Windows. $replacement indicates how characters are going to be replaced in the case they are not available in the current encoding, while $strict indicates whether unmapped codepoints will still decode; for instance, codepoint 129 which does not exist in windows-1252.
my = "Þor is mighty";say .encode("ascii", :replacement( 'Th') ).decode("ascii");# OUTPUT: «Thor is mighty»
In this case, any unknown character is going to be substituted by Th. We know in advance that the character that is not known in the ascii encoding is Þ, so we substitute it by its latin equivalent, Th. In the absence of any replacement set of characters, :replacement is understood as a Bool:
say .encode("ascii", :replacement).decode("ascii"); # OUTPUT: «?or is mighty»
If :replacement is not set or assigned a value, the error Error encoding ASCII string: could not encode codepoint 222 will be issued (in this case, since þ is codepoint 222).
Since the Blob returned by encode is the original string in normal form, and every element of a Blob is a byte, you can obtain the length in bytes of a string by calling a method that returns the size of the Blob on it:
say "þor".encode.bytes; # OUTPUT: «4»say "þor".encode.elems; # OUTPUT: «4»
(Str) routine index
multi method index(Str: Cool --> Int)multi method index(Str: Str --> Int)multi method index(Str: Cool , Cool --> Int)multi method index(Str: Str , Int --> Int)
Searches for $needle in the string starting from $pos (if present). It returns the offset into the string where $needle was found, and Nil if it was not found.
Examples:
say index "Camelia is a butterfly", "a"; # OUTPUT: «1»say index "Camelia is a butterfly", "a", 2; # OUTPUT: «6»say index "Camelia is a butterfly", "er"; # OUTPUT: «17»say index "Camelia is a butterfly", "Camel"; # OUTPUT: «0»say index "Camelia is a butterfly", "Onion"; # OUTPUT: «Nil»say index("Camelia is a butterfly", "Onion").defined ?? 'OK' !! 'NOT'; # OUTPUT: «NOT»
Other forms of index, including a sub, are inherited from Cool. Check them there.
(Str) routine rindex
multi sub rindex(Str , Str , Int = .chars --> Int)multi method rindex(Str : Str , Int = .chars --> Int)
Returns the last position of $needle in $haystack not after $startpos. Returns Nil if $needle wasn't found.
Examples:
say rindex "Camelia is a butterfly", "a"; # OUTPUT: «11»say rindex "Camelia is a butterfly", "a", 10; # OUTPUT: «6»
(Str) method indices
Defined as:
multi method indices(Str: Str , : --> List)multi method indices(Str: Str , Int , : --> List)
Searches for all occurrences of $needle in the string starting from position $start, or zero if it is not specified, and returns a List with all offsets in the string where $needle was found, or an empty list if it was not found.
If the optional parameter :overlap is specified the search continues from the index directly following the previous match, otherwise the search will continue after the previous match.
say "banana".indices("a"); # OUTPUT: «(1 3 5)»say "banana".indices("ana"); # OUTPUT: «(1)»say "banana".indices("ana", :overlap); # OUTPUT: «(1 3)»say "banana".indices("ana", 2); # OUTPUT: «(3)»
(Str) method match
method match(, :continue(:), :pos(:), :global(:), :overlap(:), :exhaustive(:), :st(:), :rd(:), :, : --> Match)
Performs a match of the string against $pat and returns a Match object if there is a successful match; it returns (Any) otherwise. Matches are stored in the default match variable $/. If $pat is not a Regex object, match will coerce the argument to a Str and then perform a literal match against $pat.
A number of optional named parameters can be specified, which alter how the match is performed.
:continue
The :continue adverb takes as an argument the position where the regex should start to search. If no position is specified for :c it will default to 0 unless $/ is set, in which case it defaults to $/.to.
:pos
Takes a position as an argument. Fails if regex cannot be matched from that position, unlike :continue.
:global
Instead of searching for just one match and returning a Match object, search for every non-overlapping match and return them in a List.
:overlap
Finds all matches including overlapping matches, but only returns one match from each starting position.
:exhaustive
Finds all possible matches of a regex, including overlapping matches and matches that start at the same position.
:st, :nd, :rd, :nth
Returns the nth match in the string. The argument can be a Numeric or an Iterable producing monotonically increasing numbers (that is, the next produced number must be larger than the previous one). The Iterable will be lazily reified and if non-monotonic sequence is encountered an exception will be thrown.
If Iterable argument is provided the return value and $/ variable will be set to a possibly-empty List of Match objects.
:x
Takes as an argument the number of matches to return, stopping once the specified number of matches has been reached. The value must be a Numeric or a Range; other values will cause .match to return a Failure containing X::Str::Match::x exception.
Examples:
say "properly".match('perl'); # OUTPUT: «｢perl｣»say "properly".match(/p.../); # OUTPUT: «｢prop｣»say "1 2 3".match([1,2,3]); # OUTPUT: «｢1 2 3｣»say "a1xa2".match(/a./, :continue(2)); # OUTPUT: «｢a2｣»say "abracadabra".match(/ a .* a /, :exhaustive);# OUTPUT: «(｢abracadabra｣ ｢abracada｣ ｢abraca｣ ｢abra｣ ｢acadabra｣ ｢acada｣ ｢aca｣ ｢adabra｣ ｢ada｣ ｢abra｣)»say 'several words here'.match(/\w+/,:global); # OUTPUT: «(｢several｣ ｢words｣ ｢here｣)»say 'abcdef'.match(/.*/, :pos(2)); # OUTPUT: «｢cdef｣»say "foo[bar][baz]".match(/../, :1st); # OUTPUT: «｢fo｣»say "foo[bar][baz]".match(/../, :2nd); # OUTPUT: «｢o[｣»say "foo[bar][baz]".match(/../, :3rd); # OUTPUT: «｢ba｣»say "foo[bar][baz]".match(/../, :4th); # OUTPUT: «｢r]｣»say "foo[bar][baz]bada".match('ba', :x(2)); # OUTPUT: «(｢ba｣ ｢ba｣)»
(Str) method Numeric
Defined as:
method Numeric(Str: --> Numeric)
Coerces the string to Numeric using semantics equivalent to val routine. Fails with X::Str::Numeric if the coercion to a number cannot be done.
Only Unicode characters with property Nd, as well as leading and trailing whitespace are allowed, with the special case of the empty string being coerced to 0. Synthetic codepoints (e.g. "7\x[308]") are forbidden.
While Nl and No characters can be used as numeric literals in the language, their conversion via Str.Numeric will fail, by design. See unival if you need to coerce such characters to Numeric.
(Str) method Int
Defined as:
method Int(Str: --> Int)
Coerces the string to Int, using the same rules as Str.Numeric.
(Str) method Rat
Defined as:
method Rat(Str: --> Rational)
Coerces the string to a Rat object, using the same rules as Str.Numeric. If the denominator is larger than 64-bits is it still kept and no degradation to Num occurs.
(Str) method Bool
Defined as:
method Bool(Str: --> Bool)
Returns False if the string is empty, True otherwise.
(Str) routine parse-base
multi sub parse-base(Str , Int --> Numeric)multi method parse-base(Str : Int --> Numeric)
Performs the reverse of base by converting a string with a base-$radix number to its Numeric equivalent. Will fail if radix is not in range 2..36 or if the string being parsed contains characters that are not valid for the specified base.
1337.base(32).parse-base(32).say; # OUTPUT: «1337»'Perl6'.parse-base(30).say; # OUTPUT: «20652936»'FF.DD'.parse-base(16).say; # OUTPUT: «255.863281»
See also: :16<FF> syntax for number literals
(Str) routine parse-names
sub parse-names(Str --> Str)method parse-names(Str : --> Str)
DEPRECATED. Use uniparse instead. Existed in Rakudo implementation as a proof of viability implementation before being renamed and will be removed when 6.e language is released.
(Str) routine uniparse
sub uniparse(Str --> Str)method uniparse(Str : --> Str)
Takes string with comma-separated Unicode names of characters and returns a string composed of those characters. Will fail if any of the characters' names are empty or not recognized. Whitespace around character names is ignored.
say "I Perl"; # OUTPUT: «I 💕 Perl»'TWO HEARTS, BUTTERFLY'.uniparse.say; # OUTPUT: «💕🦋»
Note that unlike \c[...] construct available in string interpolation, uniparse does not accept decimal numerical values. Use chr routine to convert those:
say "\c[1337]"; # OUTPUT: «Թ»say '1337'.chr; # OUTPUT: «Թ»
Note: before being standardized in 2017.12, this routine was known under its working name of parse-names. This denomination will be removed in the 6.e version.
(Str) routine split
multi sub split( Str , Str , = Inf,:, :, :, :, :)
multi sub split(Regex , Str , = Inf,:, :, :, :, :)
multi sub split(List , Str , = Inf,:, :, :, :, :)
multi method split(Str: Str , = Inf,:, :, :, :, :)
multi method split(Str: Regex , = Inf,:, :, :, :, :)
multi method split(Str: List , = Inf,:, :, :, :, :)
Splits a string up into pieces based on delimiters found in the string.
If DELIMITER is a string, it is searched for literally and not treated as a regex. If DELIMITER is the empty string, it effectively returns all characters of the string separately (plus an empty string at the begin and at the end). If PATTERN is a regular expression, then that will be used to split up the string. If DELIMITERS is a list, then all of its elements will be considered a delimiter (either a string or a regular expression) to split the string on.
The optional LIMIT indicates in how many segments the string should be split, if possible. It defaults to Inf (or *, whichever way you look at it), which means "as many as possible". Note that specifying negative limits will not produce any meaningful results.
A number of optional named parameters can be specified, which alter the result being returned. The :v, :k, :kv and :p named parameters all perform a special action with regards to the delimiter found.
:skip-empty
If specified, do not return empty strings before or after a delimiter.
:v
Also return the delimiter. If the delimiter was a regular expression, then this will be the associated Match object. Since this stringifies as the delimiter string found, you can always assume it is the delimiter string if you're not interested in further information about that particular match.
:k
Also return the index of the delimiter. Only makes sense if a list of delimiters was specified: in all other cases, this will be 0.
:kv
Also return both the index of the delimiter, as well as the delimiter.
:p
Also return the index of the delimiter and the delimiter as a Pair.
Examples:
say split(";", "a;b;c").perl; # OUTPUT: «("a", "b", "c").Seq»say split(";", "a;b;c", :v).perl; # OUTPUT: «("a", ";", "b", ";", "c").Seq»say split(";", "a;b;c", 2).perl; # OUTPUT: «("a", "b;c").Seq»say split(";", "a;b;c", 2, :v).perl; # OUTPUT: «("a", ";", "b;c").Seq»say split(";", "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d").Seq»say split(/\;/, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d").Seq»say split(<; ,>, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c", "d").Seq»say split(//, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c", "d").Seq»say split(<; ,>, "a;b;c,d", :k).perl; # OUTPUT: «("a", 0, "b", 0, "c", 1, "d").Seq»say split(<; ,>, "a;b;c,d", :kv).perl; # OUTPUT: «("a", 0, ";", "b", 0, ";", "c", 1, ",", "d").Seq»say "".split("x").perl; # OUTPUT: «("",).Seq»say "".split("x", :skip-empty).perl; # OUTPUT: «().Seq»say "abcde".split("").perl; # OUTPUT: «("", "a", "b", "c", "d", "e", "").Seq»say "abcde".split("",:skip-empty).perl; # OUTPUT: «("a", "b", "c", "d", "e").Seq»
(Str) routine comb
multi sub comb(Str , Str , = Inf)multi sub comb(Regex , Str , = Inf, Bool :)multi sub comb(Int , Str , = Inf)multi method comb(Str :)multi method comb(Str : Str , = Inf)multi method comb(Str : Regex , = Inf, Bool :)multi method comb(Str : Int , = Inf)
Searches for $matcher in $input and returns a Seq of non-overlapping matches limited to at most $limit matches. If $matcher is a Regex, each Match object is converted to a Str, unless $match is set.
If no matcher is supplied, a Seq of characters in the string is returned, as if the matcher was rx/./.
Examples:
say "abc".comb.perl; # OUTPUT: «("a", "b", "c").Seq»say 'abcdefghijk'.comb(3).perl; # OUTPUT: «("abc", "def", "ghi", "jk").Seq»say 'abcdefghijk'.comb(3, 2).perl; # OUTPUT: «("abc", "def").Seq»say comb(/\w/, "a;b;c").perl; # OUTPUT: «("a", "b", "c").Seq»say comb(/\N/, "a;b;c").perl; # OUTPUT: «("a", ";", "b", ";", "c").Seq»say comb(/\w/, "a;b;c", 2).perl; # OUTPUT: «("a", "b").Seq»say comb(/\w\;\w/, "a;b;c", 2).perl; # OUTPUT: «("a;b",).Seq»say comb(/.<(.)>/, "<>[]()").perl; # OUTPUT: «(">", "]", ")").Seq»
If the matcher is an integer value, comb behaves as if the matcher was rx/ . ** {1..$matcher} /, but which is optimized to be much faster.
Note that a Regex matcher may control which portion of the matched text is returned by using features which explicitly set the top-level capture.
(Str) routine lines
Defined as:
multi method lines(Str: )multi method lines(Str:)
Returns a list of lines (without trailing newline characters), i.e. the same as a call to $input.comb( / ^^ \N* /, $limit ) would.
Examples:
say lines("a\nb").perl; # OUTPUT: «("a", "b").Seq»say lines("a\nb").elems; # OUTPUT: «2»say "a\nb".lines.elems; # OUTPUT: «2»say "a\n".lines.elems; # OUTPUT: «1»
You can limit the number of lines returned by setting the $limit variable to a non-zero, non-Infinity value:
say <not there yet>.join("\n").lines( 2 ); # OUTPUT: «(not there)»
DEPRECATED as of 6.d language, the :count argument was used to return the total number of lines:
say <not there yet>.join("\n").lines( :count ); # OUTPUT: «3»
Use elems call on the returned Seq instead:
say <not there yet>.join("\n").lines.elems; # OUTPUT: «3»
(Str) routine words
multi method words(Str: )multi method words(Str:)
Returns a list of non-whitespace bits, i.e. the same as a call to $input.comb( / \S+ /, $limit ) would.
Examples:
say "a\nb\n".words.perl; # OUTPUT: «("a", "b").Seq»say "hello world".words.perl; # OUTPUT: «("hello", "world").Seq»say "foo:bar".words.perl; # OUTPUT: «("foo:bar",).Seq»say "foo:bar\tbaz".words.perl; # OUTPUT: «("foo:bar", "baz").Seq»
It can also be used as a subroutine, turning the first argument into the invocant. $limit is optional, but if it is provided (and not equal to Inf), it will return only the first $limit words.
say words("I will be very brief here", 2); # OUTPUT: «(I will)»
(Str) routine flip
multi sub flip(Str --> Str)multi method flip(Str: --> Str)
Returns the string reversed character by character.
Examples:
"Perl".flip; # RESULT: «lreP»"ABBA".flip; # RESULT: «ABBA»
(Str) method starts-with
multi method starts-with(Str: Str(Cool) --> Bool)
Returns True if the invocant is identical to or starts with $needle.
say "Hello, World".starts-with("Hello"); # OUTPUT: «True»say "https://perl6.org/".starts-with('ftp'); # OUTPUT: «False»
(Str) method ends-with
multi method ends-with(Str: Str(Cool) --> Bool)
Returns True if the invocant is identical to or ends with $needle.
say "Hello, World".ends-with('Hello'); # OUTPUT: «False»say "Hello, World".ends-with('ld'); # OUTPUT: «True»
(Str) method subst
multi method subst(Str: , , *)
Returns the invocant string where $matcher is replaced by $replacement (or the original string, if no match was found).
There is an in-place syntactic variant of subst spelled s/matcher/replacement/ and with adverb following the s or inside the matcher.
$matcher can be a Regex, or a literal Str. Non-Str matcher arguments of type Cool are coerced to Str for literal matching. If a Regex $matcher is used, the $/ special variable will be set to Nil (if no matches occurred), a Match object, or a List of Match objects (if multi-match options like :g are used).
Literal replacement substitution
my = "Some foo";my = .subst(/foo/, "string"); # gives 'Some string'.=subst(/foo/, "string"); # in-place substitution. $some-string is now 'Some string'
Callable
The replacement can be a Callable in which the current Match object will be placed in the $/ variable, as well as the $_ topic variable. Using a Callable as replacement is how you can refer to any of the captures created in the regex:
# Using capture from $/ variable (the $0 is the first positional capture)say 'abc123defg'.subst(/(\d+)/, );# OUTPUT: «abc before 123 after defg»# Using capture from $/ variable (the $<foo> is a named capture)say 'abc123defg'.subst(/=\d+/, );# OUTPUT: «abc before 123 after defg»# Using WhateverCode to operate on the Match given in $_:say 'abc123defg'.subst(/(\d+)/, "[ " ~ *.flip ~ " ]");# OUTPUT: «abc[ 321 ]defg»# Using a Callable to generate substitution without involving current Match:my = 41;my = "The answer is secret.";say .subst(/secret/, ); # The answer to everything# OUTPUT: «The answer is 42.»
Adverbs
The following adverbs are supported
| short | long | meaning |
|---|---|---|
| :g | :global | tries to match as often as possible |
| :nth(Int|Callable|Whatever) | only substitute the nth match; aliases: :st, :nd, :rd, and :th | |
| :ss | :samespace | preserves whitespace on substitution |
| :ii | :samecase | preserves case on substitution |
| :mm | :samemark | preserves character marks (e.g. 'ü' replaced with 'o' will result in 'ö') |
| :x(Int|Range|Whatever) | substitute exactly $x matches |
Note that only in the s/// form :ii implies :i and :ss implies :s. In the method form, the :s and :i modifiers must be added to the regex, not the subst method call.
More Examples
Here are other examples of usage:
my = "Hey foo foo foo";.subst(/foo/, "bar", :g); # global substitution - returns Hey bar bar bar.subst(/foo/, "no subst", :x(0)); # targeted substitution. Number of times to substitute. Returns back unmodified..subst(/foo/, "bar", :x(1)); #replace just the first occurrence..subst(/foo/, "bar", :nth(3)); # replace nth match alone. Replaces the third foo. Returns Hey foo foo bar
The :nth adverb has readable English-looking variants:
say 'ooooo'.subst: 'o', 'x', :1st; # OUTPUT: «xoooo»say 'ooooo'.subst: 'o', 'x', :2nd; # OUTPUT: «oxooo»say 'ooooo'.subst: 'o', 'x', :3rd; # OUTPUT: «ooxoo»say 'ooooo'.subst: 'o', 'x', :4th; # OUTPUT: «oooxo»
(Str) method subst-mutate
NOTE: .subst-mutate is deprecated in the 6.d version, and will be removed in future ones. You can use subst with .= method call assignment operator or s/// substitution operator instead.
Where subst returns the modified string and leaves the original unchanged, it is possible to mutate the original string by using subst-mutate. If the match is successful, the method returns a Match object representing the successful match, otherwise returns Nil. If :nth (or one of its aliases) with Iterable value, :g, :global, or :x arguments are used, returns a List of Match objects, or an empty List if no matches occurred.
my = "Some foo";my = .subst-mutate(/foo/, "string");say ; # OUTPUT: «Some string»say ; # OUTPUT: «｢foo｣».subst-mutate(//, '', :g); # remove every o and e, notice the :g named argument from .subst
If a Regex $matcher is used, the $/ special variable will be set to Nil (if no matches occurred), a Match object, or a List of Match objects (if multi-match options like :g are used).
(Str) routine substr
multi sub substr(Str , , ? --> Str)multi sub substr(Str , Range --> Str)multi method substr(Str : , ? --> Str)multi method substr(Str : Range --> Str)
Returns a substring of the original string, between the indices specified by $from-to's endpoints (coerced to Int) or from index $from and of length $chars.
Both $from and $chars can be specified as Callable, which will be invoked with the length of the original string and the returned value will be used as the value for the argument. If $from or $chars are not Callable, they'll be coerced to Int.
If $chars is omitted or is larger than the available characters, the string from $from until the end of the string is returned. If $from-to's starting index or $from is less than zero, X::OutOfRange exception is thrown. The $from-to's ending index is permitted to extend past the end of string, in which case it will be equivalent to the index of the last character.
say substr("Long string", 3..6); # RESULT: «g st»say substr("Long string", 6, 3); # RESULT: «tri»say substr("Long string", 6); # RESULT: «tring»say substr("Long string", 6, *-1); # RESULT: «trin»say substr("Long string", *-3, *-1); # RESULT: «in»
(Str) method substr-eq
multi method substr-eq(Str: Str(Cool) , Int(Cool) --> Bool)multi method substr-eq(Cool: Str(Cool) , Int(Cool) --> Bool)
Returns True if the $test-string exactly matches the String object, starting from the given initial index $from. For example, beginning with the string "foobar", the substring "bar" will match from index 3:
my = "foobar";say .substr-eq("bar", 3); # OUTPUT: «True»
However, the substring "barz" starting from index 3 won't match even though the first three letters of the substring do match:
my = "foobar";say .substr-eq("barz", 3); # OUTPUT: «False»
Naturally, to match the entire string, one merely matches from index 0:
my = "foobar";say .substr-eq("foobar", 0); # OUTPUT: «True»
Since this method is inherited from the Cool type, it also works on integers. Thus the integer 42 will match the value 342 starting from index 1:
my = 342;say .substr-eq(42, 1); # OUTPUT: «True»
As expected, one can match the entire value by starting at index 0:
my = 342;say .substr-eq(342, 0); # OUTPUT: «True»
Also using a different value or an incorrect starting index won't match:
my = 342;say .substr-eq(42, 3); # OUTPUT: «False»say .substr-eq(7342, 0); # OUTPUT: «False»
(Str) method substr-rw
method substr-rw(, = *)
A version of substr that returns a Proxy functioning as a writable reference to a part of a string variable. Its first argument, $from specifies the index in the string from which a substitution should occur, and its last argument, $length specifies how many characters are to be replaced. If not specified, $length defaults to the length of the string.
For example, in its method form, if one wants to take the string "abc" and replace the second character (at index 1) with the letter "z", then one does this:
my = "abc";.substr-rw(1, 1) = "z";.say; # OUTPUT: «azc»
Note that new characters can be inserted as well:
my = 'azc';.substr-rw(2, 0) = "-Zorro-"; # insert new characters BEFORE the character at index 2.say; # OUTPUT: «az-Zorro-c»
substr-rw also has a function form, so the above examples can also be written like so:
my = "abc";substr-rw(, 1, 1) = "z";.say; # OUTPUT: «azc»substr-rw(, 2, 0) = "-Zorro-";.say; # OUTPUT: «az-Zorro-c»
It is also possible to alias the writable reference returned by substr-rw for repeated operations:
my = "A character in the 'Flintstones' is: barney";~~ /(barney)/;my := substr-rw(, $0.from, $0.to-$0.from);.say;# OUTPUT: «A character in the 'Flintstones' is: barney»= "fred";.say;# OUTPUT: «A character in the 'Flintstones' is: fred»= "wilma";.say;# OUTPUT: «A character in the 'Flintstones' is: wilma»
(Str) routine samemark
multi sub samemark(Str , Str --> Str)method samemark(Str: Str --> Str)
Returns a copy of $string with the mark/accent information for each character changed such that it matches the mark/accent of the corresponding character in $pattern. If $string is longer than $pattern, the remaining characters in $string receive the same mark/accent as the last character in $pattern. If $pattern is empty no changes will be made.
Examples:
say 'åäö'.samemark('aäo'); # OUTPUT: «aäo»say 'åäö'.samemark('a'); # OUTPUT: «aao»say samemark('Pêrl', 'a'); # OUTPUT: «Perl»say samemark('aöä', ''); # OUTPUT: «aöä»
(Str) method succ
method succ(Str --> Str)
Returns the string incremented by one.
String increment is "magical". It searches for the last alphanumeric sequence that is not preceded by a dot, and increments it.
'12.34'.succ; # RESULT: «13.34»'img001.png'.succ; # RESULT: «img002.png»
The actual increment step works by mapping the last alphanumeric character to a character range it belongs to, and choosing the next character in that range, carrying to the previous letter on overflow.
'aa'.succ; # RESULT: «ab»'az'.succ; # RESULT: «ba»'109'.succ; # RESULT: «110»'α'.succ; # RESULT: «β»'a9'.succ; # RESULT: «b0»
String increment is Unicode-aware, and generally works for scripts where a character can be uniquely classified as belonging to one range of characters.
(Str) method pred
method pred(Str: --> Str)
Returns the string decremented by one.
String decrementing is "magical" just like string increment (see succ). It fails on underflow
'b0'.pred; # RESULT: «a9»'a0'.pred; # Failure'img002.png'.pred; # RESULT: «img001.png»
(Str) routine ord
multi sub ord(Str --> Int)multi method ord(Str: --> Int)
Returns the codepoint number of the base characters of the first grapheme in the string.
Example:
ord("A"); # 65"«".ord; # 171
(Str) method ords
multi method ords(Str: --> Seq)
Returns a list of Unicode codepoint numbers that describe the codepoints making up the string.
Example:
"aå«".ords; # (97 229 171)
Strings are represented as graphemes. If a character in the string is represented by multiple codepoints, then all of those codepoints will appear in the result of ords. Therefore, the number of elements in the result may not always be equal to chars, but will be equal to codes; codes computes the codepoints in a different way, so the result might be faster.
The codepoints returned will represent the string in NFC. See the NFD, NFKC, and NFKD methods if other forms are required.
(Str) method trans
multi method trans(Str: Pair \what, * --> Str)multi method trans(Str: *, :complement(:), :squash(:), :delete(:) --> Str)
Replaces one or many characters with one or many characters. Ranges are supported, both for keys and values. Regexes work as keys. In case a list of keys and values is used, substrings can be replaced as well. When called with :complement anything but the matched value or range is replaced with a single value; with :delete the matched characters without corresponding replacement are removed. Combining :complement and :delete will remove anything but the matched values, unless replacement characters have been specified, in which case, :delete would be ignored. The adverb :squash will reduce repeated matched characters to a single character.
Example:
my = 'say $x<b> && $y<a>';.=trans( '<' => '«' );.=trans( '<' => '«', '>' => '»' );.=trans( [ '<' , '>' , '&' ] =>[ '<', '>', '&' ]);.=trans( ['a'..'y'] => ['A'..'z'] );"abcdefghij".trans(/ \w/ => ''); # RESULT: «cdgh»"a123b123c".trans(['a'..'z'] => 'x', :complement); # RESULT: «axxxbxxxc»"a123b123c".trans('23' => '', :delete); # RESULT: «a1b1c»"aaa1123bb123c".trans('a'..'z' => 'A'..'Z', :squash); # RESULT: «A1123B123C»"aaa1123bb123c".trans('a'..'z' => 'x', :complement, :squash); # RESULT: «aaaxbbxc»
Please note that the behavior of the two versions of the multi method is slightly different. The first form will transpose only one character if the origin is also one character:
say "abcd".trans( "a" => "zz" ); # OUTPUT: «zbcd»say "abcd".trans( "ba" => "yz" ); # OUTPUT: «zycd»
In the second case, behavior is as expected, since the origin is more than one char long. However, if the Pair in the multi method does not have a Str as an origin or target, it is handled to the second multi method, and behavior changes:
say "abcd".trans: ["a"] => ["zz"]; # OUTPUT: «zzbcd»
In this case, neither origin nor target in the Pair are Str; the method with the Pair signature then calls the second, making this call above equivalent to "abcd".trans: ["a"] => ["zz"], (with the comma behind, making it a Positional, instead of a Pair), resulting in the behavior shown as output.
(Str) method indent
multi method indent(Int where )multi method indent(Int where )multi method indent( where )
Indents each line of the string by $steps. If $steps is negative, it outdents instead. If $steps is *, then the string is outdented to the margin:
" indented by 2 spaces\n indented even more".indent(*)eq "indented by 2 spaces\n indented even more"
(Str) method trim
method trim(Str: --> Str)
Remove leading and trailing whitespace. It can be used both as a method on strings and as a function. When used as a method it will return the trimmed string. In order to do in-place trimming, one needs to write .=trim
my = ' hello world ';say '<' ~ .trim ~ '>'; # OUTPUT: «<hello world>»say '<' ~ trim() ~ '>'; # OUTPUT: «<hello world>».trim;say '<' ~ ~ '>'; # OUTPUT: «< hello world >».=trim;say '<' ~ ~ '>'; # OUTPUT: «<hello world>»
See also trim-trailing and trim-leading.
(Str) method trim-trailing
method trim-trailing(Str: --> Str)
Removes the whitespace characters from the end of a string. See also trim.
(Str) method trim-leading
method trim-leading(Str: --> Str)
Removes the whitespace characters from the beginning of a string. See also trim.
(Str) method NFC
method NFC(Str: --> NFC)
Returns a codepoint string in NFC format (Unicode Normalization Form C / Composed).
(Str) method NFD
method NFD(Str: --> NFD)
Returns a codepoint string in NFD format (Unicode Normalization Form D / Decomposed).
(Str) method NFKC
method NFKC(Str: --> NFKC)
Returns a codepoint string in NFKC format (Unicode Normalization Form KC / Compatibility Composed).
(Str) method NFKD
method NFKD(Str: --> NFKD)
Returns a codepoint string in NFKD format (Unicode Normalization Form KD / Compatibility Decomposed).
(Str) method ACCEPTS
multi method ACCEPTS(Str: )
Returns True if the string is the same as $other.
(Str) method Capture
Defined as:
method Capture()
Throws X::Cannot::Capture.
(Str) routine val
multi sub val(Str , :)
Given a Str that may be parsable as a numeric value, it will attempt to construct the appropriate allomorph, returning one of IntStr, NumStr, RatStr or ComplexStr or a plain Str if a numeric value cannot be parsed. If the :val-or-fail adverb is provided it will return an X::Str::Numeric rather than the original string if it cannot parse the string as a number.
say val("42").^name; # OUTPUT: «IntStr»say val("42e0").^name; # OUTPUT: «NumStr»say val("42.0").^name; # OUTPUT: «RatStr»say val("42+0i").^name; # OUTPUT: «ComplexStr»
While characters belonging to the Unicode categories Nl (number letters) and No (other numbers) can be used as numeric literals in the language, they will not be converted to a number by val, by design. See unival if you need to convert such characters to Numeric.
Routines supplied by class Cool
NumStr inherits from class Cool, which provides the following routines:
(Cool) routine abs
Defined as:
sub abs(Numeric() )method abs()
Coerces the invocant (or in the sub form, the argument) to Numeric and returns the absolute value (that is, a non-negative number).
say (-2).abs; # OUTPUT: «2»say abs "6+8i"; # OUTPUT: «10»
(Cool) method conj
Defined as:
method conj()
Coerces the invocant to Numeric and returns the complex conjugate (that is, the number with the sign of the imaginary part negated).
say (1+2i).conj; # OUTPUT: «1-2i»
(Cool) routine EVAL
Defined as:
method EVAL(*)
It calls the subroutine form with the invocant as the first argument, $code, passing along named args, if any.
(Cool) routine sqrt
Defined as:
sub sqrt(Numeric(Cool) )method sqrt()
Coerces the invocant to Numeric (or in the sub form, the argument) and returns the square root, that is, a non-negative number that, when multiplied with itself, produces the original number.
say 4.sqrt; # OUTPUT: «2»say sqrt(2); # OUTPUT: «1.4142135623731»
(Cool) method sign
Defined as:
method sign()
Coerces the invocant to Numeric and returns its sign, that is, 0 if the number is 0, 1 for positive and -1 for negative values.
say 6.sign; # OUTPUT: «1»say (-6).sign; # OUTPUT: «-1»say "0".sign; # OUTPUT: «0»
(Cool) method rand
Defined as:
method rand()
Coerces the invocant to Num and returns a pseudo-random value between zero and the number.
say 1e5.rand; # OUTPUT: «33128.495184283»
(Cool) routine sin
Defined as:
sub sin(Numeric(Cool))method sin()
Coerces the invocant (or in the sub form, the argument) to Numeric, interprets it as radians, returns its sine.
say sin(0); # OUTPUT: «0»say sin(pi/4); # OUTPUT: «0.707106781186547»say sin(pi/2); # OUTPUT: «1»
Note that Perl 6 is no computer algebra system, so sin(pi) typically does not produce an exact 0, but rather a very small floating-point number.
(Cool) routine asin
Defined as:
sub asin(Numeric(Cool))method asin()
Coerces the invocant (or in the sub form, the argument) to Numeric, and returns its arc-sine in radians.
say 0.1.asin; # OUTPUT: «0.10016742116156»say asin(0.1); # OUTPUT: «0.10016742116156»
(Cool) routine cos
Defined as:
sub cos(Numeric(Cool))method cos()
Coerces the invocant (or in sub form, the argument) to Numeric, interprets it as radians, returns its cosine.
say 0.cos; # OUTPUT: «1»say pi.cos; # OUTPUT: «-1»say cos(pi/2); # OUTPUT: «6.12323399573677e-17»
(Cool) routine acos
Defined as:
sub acos(Numeric(Cool))method acos()
Coerces the invocant (or in sub form, the argument) to Numeric, and returns its arc-cosine in radians.
say 1.acos; # OUTPUT: «0»say acos(-1); # OUTPUT: «3.14159265358979»
(Cool) routine tan
Defined as:
sub tan(Numeric(Cool))method tan()
Coerces the invocant (or in sub form, the argument) to Numeric, interprets it as radians, returns its tangent.
say tan(3); # OUTPUT: «-0.142546543074278»say 3.tan; # OUTPUT: «-0.142546543074278»
(Cool) routine atan
Defined as:
sub atan(Numeric(Cool))method atan()
Coerces the invocant (or in sub form, the argument) to Numeric, and returns its arc-tangent in radians.
say atan(3); # OUTPUT: «1.24904577239825»say 3.atan; # OUTPUT: «1.24904577239825»
(Cool) routine atan2
Defined as:
method atan2( = 1e0)
Coerces self and argument to Numeric, using them to compute the two-argument arc-tangent in radians.
say 3.atan2; # OUTPUT: «1.24904577239825»say ⅔.atan2(⅓); # OUTPUT: «1.1071487177940904»
The first argument defaults to 1, so in the first case the function will return the angle θ in radians between a vector that goes from origin to the point (3, 1) and the x axis.
(Cool) routine sec
Defined as:
sub sec(Numeric(Cool))method sec()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its secant, that is, the reciprocal of its cosine.
say 45.sec; # OUTPUT: «1.90359440740442»say sec(45); # OUTPUT: «1.90359440740442»
(Cool) routine asec
Defined as:
sub asec(Numeric(Cool))method asec()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-secant in radians.
say 1.asec; # OUTPUT: «0»say sqrt(2).asec; # OUTPUT: «0.785398163397448»
(Cool) routine cosec
Defined as:
sub cosec(Numeric(Cool))method cosec()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its cosecant, that is, the reciprocal of its sine.
say 0.45.cosec; # OUTPUT: «2.29903273150897»say cosec(0.45); # OUTPUT: «2.29903273150897»
(Cool) routine acosec
Defined as:
sub acosec(Numeric(Cool))method acosec()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-cosecant in radians.
say 45.acosec; # OUTPUT: «0.0222240516182672»say acosec(45) # OUTPUT: «0.0222240516182672»
(Cool) routine cotan
Defined as:
sub cotan(Numeric(Cool))method cotan()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians, returns its cotangent, that is, the reciprocal of its tangent.
say 45.cotan; # OUTPUT: «0.617369623783555»say cotan(45); # OUTPUT: «0.617369623783555»
(Cool) routine acotan
Defined as:
sub acotan(Numeric(Cool))method acotan()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its arc-cotangent in radians.
say 45.acotan; # OUTPUT: «0.0222185653267191»say acotan(45) # OUTPUT: «0.0222185653267191»
(Cool) routine sinh
Defined as:
sub sinh(Numeric(Cool))method sinh()
Coerces the invocant (or in method form, its argument) to Numeric, and returns its Sine hyperbolicus.
say 1.sinh; # OUTPUT: «1.1752011936438»say sinh(1); # OUTPUT: «1.1752011936438»
(Cool) routine asinh
Defined as:
sub asinh(Numeric(Cool))method asinh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse Sine hyperbolicus.
say 1.asinh; # OUTPUT: «0.881373587019543»say asinh(1); # OUTPUT: «0.881373587019543»
(Cool) routine cosh
Defined as:
sub cosh(Numeric(Cool))method cosh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Cosine hyperbolicus.
say cosh(0.5); # OUTPUT: «1.12762596520638»
(Cool) routine acosh
Defined as:
sub acosh(Numeric(Cool))method acosh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse Cosine hyperbolicus.
say acosh(45); # OUTPUT: «4.4996861906715»
(Cool) routine tanh
Defined as:
sub tanh(Numeric(Cool))method tanh()
Coerces the invocant (or in sub form, its argument) to Numeric, interprets it as radians and returns its Tangent hyperbolicus.
say tanh(0.5); # OUTPUT: «0.46211715726001»say tanh(atanh(0.5)); # OUTPUT: «0.5»
(Cool) routine atanh
Defined as:
sub atanh(Numeric(Cool))method atanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse tangent hyperbolicus.
say atanh(0.5); # OUTPUT: «0.549306144334055»
(Cool) routine sech
Defined as:
sub sech(Numeric(Cool))method sech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Secant hyperbolicus.
say 0.sech; # OUTPUT: «1»
(Cool) routine asech
Defined as:
sub asech(Numeric(Cool))method asech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic secant.
say 0.8.asech; # OUTPUT: «0.693147180559945»
(Cool) routine cosech
Defined as:
sub cosech(Numeric(Cool))method cosech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Hyperbolic cosecant.
say cosech(pi/2); # OUTPUT: «0.434537208094696»
(Cool) routine acosech
Defined as:
sub acosech(Numeric(Cool))method acosech()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic cosecant.
say acosech(4.5); # OUTPUT: «0.220432720979802»
(Cool) routine cotanh
Defined as:
sub cotanh(Numeric(Cool))method cotanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Hyperbolic cotangent.
say cotanh(pi); # OUTPUT: «1.00374187319732»
(Cool) routine acotanh
Defined as:
sub acotanh(Numeric(Cool))method acotanh()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns its Inverse hyperbolic cotangent.
say acotanh(2.5); # OUTPUT: «0.423648930193602»
(Cool) routine cis
Defined as:
sub cis(Numeric(Cool))method cis()
Coerces the invocant (or in sub form, its argument) to Numeric, and returns cos(argument) + i*sin(argument).
say cis(pi/4); # OUTPUT: «0.707106781186548+0.707106781186547i»
(Cool) routine log
Defined as:
multi sub log(Numeric(Cool) , Numeric(Cool) ?)multi method log(Cool: Cool ?)
Coerces the arguments (including the invocant in the method form) to Numeric, and returns its Logarithm to base $base, or to base e (Euler's Number) if no base was supplied (Natural logarithm). Returns NaN if $base is negative. Throws an exception if $base is 1.
say (e*e).log; # OUTPUT: «2»
(Cool) routine log10
Defined as:
multi sub log10(Cool(Numeric))multi method log10()
Coerces the invocant (or in the sub form, the invocant) to Numeric, and returns its Logarithm to base 10, that is, a number that approximately produces the original number when raised to the power of 10. Returns NaN for negative arguments and -Inf for 0.
say log10(1001); # OUTPUT: «3.00043407747932»
(Cool) routine exp
Defined as:
multi sub exp(Cool , Cool ?)multi method exp(Cool: Cool ?)
Coerces the arguments (including the invocant in the method from) to Numeric, and returns $base raised to the power of the first number. If no $base is supplied, e (Euler's Number) is used.
say 0.exp; # OUTPUT: «1»say 1.exp; # OUTPUT: «2.71828182845905»say 10.exp; # OUTPUT: «22026.4657948067»
(Cool) method unpolar
Defined as:
method unpolar(Numeric(Cool))
Coerces the arguments (including the invocant in the method form) to Numeric, and returns a complex number from the given polar coordinates. The invocant (or the first argument in sub form) is the magnitude while the argument (i.e. the second argument in sub form) is the angle. The angle is assumed to be in radians.
say sqrt(2).unpolar(pi/4); # OUTPUT: «1+1i»
(Cool) routine round
Defined as:
multi sub round(Numeric(Cool))multi method round(Cool: = 1)
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it to the unit of $unit. If $unit is 1, rounds to the nearest integer.
say 1.7.round; # OUTPUT: «2»say 1.07.round(0.1); # OUTPUT: «1.1»say 21.round(10); # OUTPUT: «20»
Always rounds up if the number is at mid-point:
say (−.5 ).round; # OUTPUT: «0»say ( .5 ).round; # OUTPUT: «1»say (−.55).round(.1); # OUTPUT: «-0.5»say ( .55).round(.1); # OUTPUT: «0.6»
Pay attention to types when using this method, as ending up with the wrong type may affect the precision you seek to achieve. For Real types, the type of the result is the type of the argument (Complex argument gets coerced to Real, ending up a Num). If rounding a Complex, the result is Complex as well, regardless of the type of the argument.
9930972392403501.round(1) .perl.say; # OUTPUT: «9930972392403501»9930972392403501.round(1e0) .perl.say; # OUTPUT: «9.9309723924035e+15»9930972392403501.round(1e0).Int.perl.say; # OUTPUT: «9930972392403500»
(Cool) routine floor
Defined as:
multi sub floor(Numeric(Cool))multi method floor
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it downwards to the nearest integer.
say "1.99".floor; # OUTPUT: «1»say "-1.9".floor; # OUTPUT: «-2»say 0.floor; # OUTPUT: «0»
(Cool) method fmt
Defined as:
method fmt( = '%s')
Uses $format to return a formatted representation of the invocant; equivalent to calling sprintf with $format as format and the invocant as the second argument. The $format will be coerced to Stringy and defaults to '%s'.
For more information about formats strings, see sprintf.
say 11.fmt('This Int equals %03d'); # OUTPUT: «This Int equals 011»say '16'.fmt('Hexadecimal %x'); # OUTPUT: «Hexadecimal 10»
(Cool) routine ceiling
Defined as:
multi sub ceiling(Numeric(Cool))multi method ceiling
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it upwards to the nearest integer.
say "1".ceiling; # OUTPUT: «1»say "-0.9".ceiling; # OUTPUT: «0»say "42.1".ceiling; # OUTPUT: «43»
(Cool) routine truncate
Defined as:
multi sub truncate(Numeric(Cool))multi method truncate()
Coerces the invocant (or in sub form, its argument) to Numeric, and rounds it towards zero.
say 1.2.truncate; # OUTPUT: «1»say truncate -1.2; # OUTPUT: «-1»
(Cool) routine ord
Defined as:
sub ord(Str(Cool))method ord()
Coerces the invocant (or in sub form, its argument) to Str, and returns the Unicode code point number of the first code point.
say 'a'.ord; # OUTPUT: «97»
The inverse operation is chr.
Mnemonic: returns an ordinal number
(Cool) method path
Defined as:
method path()
DEPRECATED. It's been deprecated as of the 6.d version. Will be removed in the next ones.
Stringifies the invocant and converts it to IO::Path object. Use the .IO method instead.
(Cool) routine chr
Defined as:
sub chr(Int(Cool))method chr()
Coerces the invocant (or in sub form, its argument) to Int, interprets it as a Unicode code points, and returns a string made of that code point.
say '65'.chr; # OUTPUT: «A»
The inverse operation is ord.
Mnemonic: turns an integer into a character.
(Cool) routine chars
Defined as:
multi sub chars(Cool )multi sub chars(Str )multi sub chars(str --> int)method chars(--> Int)
Coerces the invocant (or in sub form, its argument) to Str, and returns the number of characters in the string. Please note that on the JVM, you currently get codepoints instead of graphemes.
say 'møp'.chars; # OUTPUT: «3»say 'ã̷̠̬̊'.chars; # OUTPUT: «1»say '👨👩👧👦🏿'.chars; # OUTPUT: «1»
If the string is native, the number of chars will be also returned as a native int.
Graphemes are user visible characters. That is, this is what the user thinks of as a “character”.
Graphemes can contain more than one codepoint. Typically the number of graphemes and codepoints differs when Prepend or Extend characters are involved (also known as Combining characters), but there are many other cases when this may happen. Another example is \c[ZWJ] (Zero-width joiner).
You can check Grapheme_Cluster_Break property of a character in order to see how it is going to behave:
say ‘ã̷̠̬̊’.uniprops(‘Grapheme_Cluster_Break’); # OUTPUT: «(Other Extend Extend Extend Extend)»say ‘👨👩👧👦🏿’.uniprops(‘Grapheme_Cluster_Break’); # OUTPUT: «(E_Base_GAZ ZWJ E_Base_GAZ ZWJ E_Base_GAZ ZWJ E_Base_GAZ E_Modifier)»
You can read more about graphemes in the Unicode Standard, which Perl 6 tightly follows, using a method called NFG, normal form graphemes for efficiently representing them.
(Cool) routine codes
Defined as:
sub codes(Str(Cool))method codes()
Coerces the invocant (or in sub form, its argument) to Str, and returns the number of Unicode code points.
say 'møp'.codes; # OUTPUT: «3»
The same result will be obtained with
say +'møp'.ords; # OUTPUT: «3»
ords first obtains the actual codepoints, so there might be a difference in speed.
(Cool) routine flip
Defined as:
sub flip(Cool --> Str)method flip()
Coerces the invocant (or in sub form, its argument) to Str, and returns a reversed version.
say 421.flip; # OUTPUT: «124»
(Cool) routine trim
Defined as:
sub trim(Str(Cool))method trim()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with both leading and trailing whitespace stripped.
my = ' abc '.trim;say "<$stripped>"; # OUTPUT: «<abc>»
(Cool) routine trim-leading
Defined as:
sub trim-leading(Str(Cool))method trim-leading()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with leading whitespace stripped.
my = ' abc '.trim-leading;say "<$stripped>"; # OUTPUT: «<abc >»
(Cool) routine trim-trailing
Defined as:
sub trim-trailing(Str(Cool))method trim-trailing()
Coerces the invocant (or in sub form, its argument) to Str, and returns the string with trailing whitespace stripped.
my = ' abc '.trim-trailing;say "<$stripped>"; # OUTPUT: «< abc>»
(Cool) routine lc
Defined as:
sub lc(Str(Cool))method lc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it case-folded to lower case.
say "ABC".lc; # OUTPUT: «abc»
(Cool) routine uc
Defined as:
sub uc(Str(Cool))method uc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it case-folded to upper case (capital letters).
say "Abc".uc; # OUTPUT: «ABC»
(Cool) routine fc
Defined as:
sub fc(Str(Cool))method fc()
Coerces the invocant (or in sub form, its argument) to Str, and returns the result a Unicode "case fold" operation suitable for doing caseless string comparisons. (In general, the returned string is unlikely to be useful for any purpose other than comparison.)
say "groß".fc; # OUTPUT: «gross»
(Cool) routine tc
Defined as:
sub tc(Str(Cool))method tc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the first letter case-folded to title case (or where not available, upper case).
say "abC".tc; # OUTPUT: «AbC»
(Cool) routine tclc
Defined as:
sub tclc(Str(Cool))method tclc()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the first letter case-folded to title case (or where not available, upper case), and the rest of the string case-folded to lower case.
say 'abC'.tclc; # OUTPUT: «Abc»
(Cool) routine wordcase
Defined as:
sub wordcase(Str(Cool) , : = , Mu : = True)method wordcase(: = , Mu : = True)
Coerces the invocant (or in sub form, the first argument) to Str, and filters each word that smartmatches against $where through the &filter. With the default filter (first character to upper case, rest to lower) and matcher (which accepts everything), this title-cases each word:
say "perl 6 programming".wordcase; # OUTPUT: «Perl 6 Programming»
With a matcher:
say "have fun working on perl".wordcase(:where());# Have fun Working on Perl
With a customer filter too:
say "have fun working on perl".wordcase(:filter(), :where());# HAVE fun WORKING on PERL
(Cool) routine samecase
Defined as:
sub samecase(Cool , Cool )method samecase(Cool: Cool )
Coerces the invocant (or in sub form, the first argument) to Str, and returns a copy of $string with case information for each individual character changed according to $pattern.
Note: The pattern string can contain three types of characters, i.e. uppercase, lowercase and caseless. For a given character in $pattern its case information determines the case of the corresponding character in the result.
If $string is longer than $pattern, the case information from the last character of $pattern is applied to the remaining characters of $string.
say "perL 6".samecase("A__a__"); # OUTPUT: «Perl 6»say "pERL 6".samecase("Ab"); # OUTPUT: «Perl 6»
(Cool) routine uniprop
Defined as:
multi sub uniprop(Str, |c)multi sub uniprop(Int )multi sub uniprop(Int , Stringy )multi method uniprop(|c)
Returns the unicode property of the first character. If no property is specified returns the General Category. Returns a Bool for Boolean properties. A uniprops routine can be used to get the property for every character in a string.
say 'a'.uniprop; # OUTPUT: «Ll»say '1'.uniprop; # OUTPUT: «Nd»say 'a'.uniprop('Alphabetic'); # OUTPUT: «True»say '1'.uniprop('Alphabetic'); # OUTPUT: «False»
(Cool) sub uniprops
Defined as:
sub uniprops(Str , Stringy = "General_Category")
Interprets the invocant as a Str, and returns the unicode property for each character as a Seq. If no property is specified returns the General Category. Returns a Bool for Boolean properties. Similar to uniprop, but for each character in the passed string.
(Cool) routine uniname
Defined as:
sub uniname(Str(Cool) --> Str)method uniname(--> Str)
Interprets the invocant or first argument as a Str, and returns the Unicode codepoint name of the first codepoint of the first character. See uninames for a routine that works with multiple codepoints, and uniparse for the opposite direction.
# Camelia in Unicodesay ‘»ö«’.uniname;# OUTPUT: «"RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK"»say "Ḍ̇".uniname; # Note, doesn't show "COMBINING DOT ABOVE"# OUTPUT: «"LATIN CAPITAL LETTER D WITH DOT BELOW"»# Find the char with the longest Unicode name.say (0..0x1FFFF).sort(*.uniname.chars)[].chr.uniname;# OUTPUT: ««ARABIC LIGATURE UIGHUR KIRGHIZ YEH WITH HAMZA ABOVE WITH ALEF MAKSURA INITIAL FORM»»
(Cool) routine uninames
Defined as:
sub uninames(Str)method uninames()
Returns of a Seq of Unicode names for the all the codepoints in the Str provided.
say ‘»ö«’.uninames.perl;# OUTPUT: «("RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK", "LATIN SMALL LETTER O WITH DIAERESIS", "LEFT-POINTING DOUBLE ANGLE QUOTATION MARK").Seq»
Note this example, which gets a Seq where each element is a Seq of all the codepoints in that character.
say "Ḍ̇'oh".comb>>.uninames.perl;# OUTPUT: «(("LATIN CAPITAL LETTER D WITH DOT BELOW", "COMBINING DOT ABOVE").Seq, ("APOSTROPHE",).Seq, ("LATIN SMALL LETTER O",).Seq, ("LATIN SMALL LETTER H",).Seq)»
See uniparse for the opposite direction.
(Cool) routine unimatch
Defined as:
multi sub unimatch(Str , |c)multi unimatch(Int , Stringy , Stringy = )
Checks if the given integer codepoint or the first letter of the string given have a unicode property equal to the value you give. If you supply the Unicode property to be checked it will only return True if that property matches the given value.
say unimatch 'A', 'Latin'; # OUTPUT: «True»say unimatch 'A', 'Latin', 'Script'; # OUTPUT: «True»say unimatch 'A', 'Ll'; # OUTPUT: «True»
(Cool) routine chop
Defined as:
sub chop(Str(Cool))method chop()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the last character removed.
say 'perl'.chop; # OUTPUT: «per»
(Cool) routine chomp
Defined as:
sub chomp(Str(Cool))method chomp()
Coerces the invocant (or in sub form, its argument) to Str, and returns it with the last character removed, if it is a logical newline.
say 'ab'.chomp.chars; # OUTPUT: «2»say "a\n".chomp.chars; # OUTPUT: «1»
(Cool) routine substr
Defined as:
sub substr(Str(Cool) , |c)method substr(|c)
Coerces the invocant (or in the sub form, the first argument) to Str, and calls Str.substr with the arguments.
(Cool) routine substr-rw
Defined as:
multi method substr-rw(|) is rwmulti sub substr-rw(|) is rw
Coerces the invocant (or in the sub form, the first argument) to Str, and calls Str.substr-rw with the arguments.
(Cool) routine ords
Defined as:
sub ords(Str(Cool) )method ords()
Coerces the invocant (or in the sub form, the first argument) to Str, and returns a list of Unicode codepoints for each character.
say "Camelia".ords; # OUTPUT: «67 97 109 101 108 105 97»say ords 10; # OUTPUT: «49 48»
This is the list-returning version of ord. The inverse operation in chrs. If you are only interested in the number of codepoints, codes is a possibly faster option.
(Cool) routine chrs
Defined as:
sub chrs(* --> Str)method chrs()
Coerces the invocant (or in the sub form, the argument list) to a list of integers, and returns the string created by interpreting each integer as a Unicode codepoint, and joining the characters.
say <67 97 109 101 108 105 97>.chrs; # OUTPUT: «Camelia»
This is the list-input version of chr. The inverse operation is ords.
(Cool) routine split
Defined as:
multi sub split( Str , Str(Cool) , = Inf, :, :, :, :, :)multi sub split(Regex , Str(Cool) , = Inf, :, :, :, :, :)multi sub split(, Str(Cool) , = Inf, :, :, :, :, :)multi method split( Str , = Inf, :, :, :, :, :)multi method split(Regex , = Inf, :, :, :, :, :)multi method split(, = Inf, :, :, :, :, :)
Coerces the invocant (or in the sub form, the second argument) to Str, and splits it into pieces based on delimiters found in the string.
If $delimiter is a string, it is searched for literally and not treated as a regex. You can also provide multiple delimiters by specifying them as a list; mixing Cool and Regex objects is OK.
say split(';', "a;b;c").perl; # OUTPUT: «("a", "b", "c")»say split(';', "a;b;c", 2).perl; # OUTPUT: «("a", "b;c").Seq»say split(';', "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d")»say split(/\;/, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c,d")»say split(//, "a;b;c,d").perl; # OUTPUT: «("a", "b", "c", "d")»say split(['a', /b+/, 4], '1a2bb345').perl; # OUTPUT: «("1", "2", "3", "5")»
By default, split omits the matches, and returns a list of only those parts of the string that did not match. Specifying one of the :k, :v, :kv, :p adverbs changes that. Think of the matches as a list that is interleaved with the non-matching parts.
The :v interleaves the values of that list, which will be either Match objects, if a Regex was used as a matcher in the split, or Str objects, if a Cool was used as matcher. If multiple delimiters are specified, Match objects will be generated for all of them, unless all of the delimiters are Cool.
say 'abc'.split(/b/, :v); # OUTPUT: «(a ｢b｣ c)»say 'abc'.split('b', :v); # OUTPUT: «(a b c)»
:k interleaves the keys, that is, the indexes:
say 'abc'.split(/b/, :k); # OUTPUT: «(a 0 c)»
:kv adds both indexes and matches:
say 'abc'.split(/b/, :kv); # OUTPUT: «(a 0 ｢b｣ c)»
and :p adds them as Pairs, using the same types for values as :v does:
say 'abc'.split(/b/, :p); # OUTPUT: «(a 0 => ｢b｣ c)»say 'abc'.split('b', :p); # OUTPUT: «(a 0 => b c)»
You can only use one of the :k, :v, :kv, :p adverbs in a single call to split.
Note that empty chunks are not removed from the result list. For that behavior, use the :skip-empty named argument:
say ("f,,b,c,d".split: /","/ ).perl; # OUTPUT: «("f", "", "b", "c", "d")»say ("f,,b,c,d".split: /","/, :skip-empty).perl; # OUTPUT: «("f", "b", "c", "d")»
(Cool) routine lines
Defined as:
sub lines(Str(Cool))method lines()
Coerces the invocant (and in sub form, the argument) to Str, decomposes it into lines (with the newline characters stripped), and returns the list of lines.
say lines("a\nb\n").join('|'); # OUTPUT: «a|b»say "some\nmore\nlines".lines.elems; # OUTPUT: «3»
This method can be used as part of an IO::Path to process a file line-by-line, since IO::Path objects inherit from Cool, e.g.:
for 'huge-csv'.IO.lines -># or if you'll be processing latermy = 'huge-csv'.IO.lines;
Without any arguments, sub lines operates on $*ARGFILES, which defaults to $*IN in the absence of any filenames.
To modify values in place use is copy to force a writable container.
for .lines -> is copy
(Cool) method words
Defined as:
method words(Cool: |c)
Coerces the invocant (or first argument, if it is called as a subroutine) to Str, and returns a list of words that make up the string. Check Str.words for additional arguments and its meaning.
say <The quick brown fox>.words.join('|'); # OUTPUT: «The|quick|brown|fox»say <The quick brown fox>.words(2).join('|'); # OUTPUT: «The|quick»
Cool is the base class for many other classes, and some of them, like Match, can be converted to a string. This is what happens in this case:
say ( "easy come, easy goes" ~~ m:g/(ea\w+)/).words(Inf);# OUTPUT: «(easy easy)»say words( "easy come, easy goes" ~~ m:g/(ea\w+)/ , ∞);# OUTPUT: «(easy easy)»
The example above illustrates two of the ways words can be invoked, with the first argument turned into invocant by its signature. Of course, Inf is the default value of the second argument, so in both cases (and forms) it can be simply omitted.
Only whitespace (including no-break space) counts as word boundaries
say <Don't we ♥ Perl 6>.words.join('|'); # OUTPUT: «Don't|we|♥|Perl|6»
In this case, Perl 6 includes an (visible only in the source) no-break space; words still splits the (resulting) Str on it, even if the original array only had 4 elements:
say <Don't we ♥ Perl 6>.join("|"); # OUTPUT: «Don't|we|♥|Perl 6»
Please see Str.words for more examples and ways to invoke it.
(Cool) routine comb
Defined as:
multi sub comb(Regex , Cool , = *)multi sub comb(Str , Cool , = *)multi sub comb(Int , Cool , = *)multi method comb(|c)
Returns a Seq of all (or if supplied, at most $limit) matches of the invocant (method form) or the second argument (sub form) against the Regex, string or defined number.
say "6 or 12".comb(/\d+/).join(", "); # OUTPUT: «6, 12»say comb(/\d /,(11..30)).join("--");# OUTPUT:# «11--12--13--14--15--16--17--18--19--21--22--23--24--25--26--27--28--29»
The second statement exemplifies the first form of comb, with a Regex that excludes multiples of ten, and a Range (which is Cool) as $input. comb stringifies the Range before applying .comb on the resulting string. Check Str.comb for its effect on different kind of input strings. When the first argument is an integer, it indicates the (maximum) size of the chunks the input is going to be divided in
say comb(3,[3,33,333,3333]).join("*"); # OUTPUT: «3 3*3 3*33 *333*3»
In this case the input is a list, which after transformation to Str (which includes the spaces) is divided in chunks of size 3.
(Cool) method contains
Defined as:
method contains(Cool: |c)
Coerces the invocant Str, and calls Str.contains on it. Please refer to that version of the method for arguments and general syntax.
say 123.contains("2")# OUTPUT: «True»
Since Int is a subclass of Cool, 123 is coerced to a Str and then contains is called on it.
say (1,1, * + * … * > 250).contains(233)# OUTPUT: «True»
Seqs are also subclasses of Cool, and they are stringified to a comma-separated form. In this case we are also using an Int, which is going to be stringified also; "233" is included in that sequence, so it returns True. Please note that this sequence is not lazy; the stringification of lazy sequences does not include each and every one of their components for obvious reasons.
(Cool) routine index
Defined as:
multi sub index(Cool , Cool , Cool = 0)method index(Cool: |c)
Coerces the first two arguments (in method form, also counting the invocant) to a Str, and searches for $needle in the string $s starting from $startpos. It returns the offset into the string where $needle was found, and an undefined value if it was not found.
See the documentation in type Str for examples.
(Cool) routine rindex
Defined as:
multi sub rindex(Str(Cool) , Str(Cool) , Int(Cool) = .chars)multi method rindex(Str(Cool) : Str(Cool) , Int(Cool) = .chars)
Coerces the first two arguments (including the invocant in method form) to Str and $startpos to Int, and returns the last position of $needle in $haystack not after $startpos. Returns an undefined value if $needle wasn't found.
See the documentation in type Str for examples.
(Cool) method match
Defined as:
multi method match(Cool: , *)
Coerces the invocant to Str and calls the method match on it.
(Cool) routine roots
Defined as:
multi sub roots(Numeric(Cool) , Int(Cool) )multi method roots(Int(Cool) )
Coerces the first argument (and in method form, the invocant) to Numeric and the second ($n) to Int, and produces a list of $n Complex $n-roots, which means numbers that, raised to the $nth power, approximately produce the original number.
For example
my = 16;my = .roots(4);say ;for -># OUTPUT:«2+0i 1.22464679914735e-16+2i -2+2.44929359829471e-16i -3.67394039744206e-16-2i»# OUTPUT:«1.77635683940025e-15»# OUTPUT:«4.30267170434156e-15»# OUTPUT:«8.03651692704705e-15»# OUTPUT:«1.04441561648202e-14»
(Cool) method match
Defined as:
method match(|)
Coerces the invocant to Stringy and calls Str.match.
(Cool) method subst
Defined as:
method subst(|)
Coerces the invocant to Stringy and calls Str.subst.
(Cool) method trans
Defined as:
method trans(|)
Coerces the invocant to Str and calls Str.trans
(Cool) method IO
Defined as:
method IO(--> IO::Path)
Coerces the invocant to IO::Path.
.say for '.'.IO.dir; # gives a directory listing
Routines supplied by role Real
NumStr inherits from class Num, which does role Real, which provides the following routines:
(Real) method Bridge
Defined as:
method Bridge(Real:)
Default implementation coerces the invocant to Num and that's the behavior of this method in core Real types. This method primarily exist to make it easy to implement custom Real types by users, with the Bridge method returning one of the core Real types (NOT necessarily a Num) that best represent the custom Real type. In turn, this lets all the core operators and methods obtain a usable value they can work with.
As an example, we can implement a custom Temperature type. It has a unit of measure and the value, which are given during instantiation. We can implement custom operators or conversion methods that work with this type. When it comes to regular mathematical operators, however, we can simply use the .Bridge method to convert the Temperature to Kelvin expressed in one of the core numeric types:
is Realsub postfix:<℃>sub postfix:<℉>sub postfix:<K>my := 36.6℃;my := 451℉;my := 5778K;say ; # OUTPUT: «36.6 degrees C»say + + ; # OUTPUT: «6593.677777777778»say 123K + 456K; # OUTPUT: «579»
As we can see from the last two lines of the output, the type of the bridged result is not forced to be any particular core type. It is a Rat, when we instantiated Temperature with a Rat or when conversion was involved, and it is an Int when we instantiated Temperature with an Int.
(Real) method Complex
method Complex(Real: --> Complex)
Converts the number to a Complex with the number converted to a Num as its real part and 0e0 as the imaginary part.
(Real) method Rat
method Rat(Real: Real = 1e-6)
Converts the number to a Rat with the precision $epsilon.
(Real) method Real
Defined as:
multi method Real(Real: --> Real)multi method Real(Real: --> Real)
The :D variant simply returns the invocant. The :U variant issues a warning about using an uninitialized value in numeric context and then returns self.new.
(Real) routine rand
sub term:<rand> (--> Num)method rand(Real: --> Real)
Returns a pseudo-random number between zero (inclusive) and the number (non-inclusive). The Bridge method is used to coerce the Real to a numeric that supports rand method.
The term form returns a pseudo-random Num between 0e0 (inclusive) and 1e0 (non-inclusive.)
(Real) method sign
method sign(Real:)
Returns -1 if the number is negative, 0 if it is zero and 1 otherwise.
(Real) method round
method round(Real: = 1)
Rounds the number to scale $scale. If $scale is 1, rounds to an integer. If scale is 0.1, rounds to one digit after the comma etc.
(Real) method floor
method floor(Real --> Int)
Return the largest integer not greater than the number.
(Real) method ceiling
method ceiling(Real --> Int)
Returns the smallest integer not less than the number.
(Real) method truncate
method truncate(Real --> Int)
Rounds the number towards zero.
(Real) method polymod
method polymod(Real: +)
Returns the remainders after applying sequentially all divisors in the @mods argument; the last element of the array will be the last remainder.
say (1e8+1).polymod(10 xx 8); # OUTPUT: «(1 0 0 0 0 0 0 0 1)»
10 xx 8 is simply an array with eight number 10s; the first division by 10 will return 1 as a remainder, while the rest, up to the last, will return 0. With 8 divisors, as above, the result will have one more elements, in this case for the last remainder.
(Real) method base
method base(Real: Int where 2..36, ? --> Str)
Converts the number to a string, using $base as base. For $base larger than ten, capital Latin letters are used.
255.base(16); # 'FF'
The optional $digits argument asks for that many digits of fraction (which may not be negative). If omitted, a reasonable default is chosen based on type. For Int this default is 0. For Num, the default is 8. For Rational, the number of places is scaled to the size of the denominator, with a minimum of 6.
A special value of Whatever (*) can be given as $digits, which functions the same as when $digits is not specified for all Real types except the Rationals. For Rationals, the Whatever indicates that you wish all of the possible digits of the fractional part, but use caution: since there's no detection of repeating fractional parts (the algorithm will eventually stop after generating 2**63 digits).
The final digit produced is always rounded.
say pi.base(10, 3); # OUTPUT: «3.142»say (1/128).base(10, *); # OUTPUT: «0.0078125»say (1/100).base(10, *); # OUTPUT: «0.01»say (1/3) .base(10, *); # WRONG: endlessly repeating fractional part
For reverse operation, see parse-base