Perl 6 Documentationclass Num
Floating-point number
is Cool does Real
A Num object stores a floating-point number. It is immutable. On most platforms, it's an IEEE 754 64-bit floating point numbers, aka "double precision".
Inf
The value Inf is an instance of Num and represents value that's too large to represent in 64-bit double-precision floating point number (roughly, above 1.7976931348623158e308 for positive Inf and below -1.7976931348623157e308 for negative Inf) as well as returned from certain operations as defined by the IEEE 754-2008 standard.
say 2e300 ** 2e300; # OUTPUT: «Inf»say (-1/0).Num; # OUTPUT: «-Inf»
The ∞ U+221E Unicode character can be used instead of the word Inf and can be handy when Inf would otherwise require an unspace, such as when writing Complex numbers:
say Inf+Inf\i; # Backslash (unspace) before `i` requiredsay ∞+∞i; # No backslash is needed
Note that there are just two infinities (positive and negative), so even if an operation that would instinctively give a "larger" infinity is performed, the result in still an infinity of the original magnitude. The infinities can be compared, operated and used as an argument as if they were simply a number that's too big to represent or to signify "without bounds" or limits:
say ∞²; # OUTPUT: «Inf»say 42 + Inf === ∞; # OUTPUT: «True»say atan ∞; # OUTPUT: «1.5707963267949»say -∞ < 42 < ∞; # OUTPUT: «True»my := 1, 2, 4, 8 ... Inf; # Infinite sequence (no limits)
In some cases, it's used as an implicit value to represent "all of them"
say "House of M".comb(3,Inf).join("←X→");# OUTPUT: «Hou←X→se ←X→of ←X→M»
In the example above, Inf can be eliminated, since it's the default value for the second argument of .comb, used to indicate how many parts should be returned.
Division of an infinity by another infinity results in a NaN:
say ∞/∞; # OUTPUT: «NaN»
NaN
The value NaN is an instance of Num and represents a floating point not-a-number value, which is returned from some routines where a concrete number as the answer is not defined, but a Numeric value is still acceptable. NaN is defined and boolifies to True, but is not numerically equal to any value (including itself).
say cos ∞; # OUTPUT: «NaN»say (0/0).Num; # OUTPUT: «NaN»
To test for NaN, use isNaN method or === operator:
say (0/0).isNaN; # OUTPUT: «True»say (0/0).Num === NaN; # OUTPUT: «True»
method rand
method rand(Num: --> Num)
Returns a pseudo random number between 0 and the invocant.
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.
method Capture
Defined as:
method Capture()
Throws X::Cannot::Capture.
Int
method Int(Num:)
Converts the number to an Int. Fails with X::Numeric::CannotConvert if the invocant is a NaN or Inf/-Inf. No rounding is performed.
Rat
method Rat(Num: Real = 1e-6)
Converts the number to a Rat with $epsilon precision. If the invocant is a Inf, -Inf, or a NaN, converts them to a Rat with 0 denominator and 1, -1, or 0 numerator, respectively.
FatRat
method FatRat(Num: Real = 1e-6)
Converts the number to a FatRat with the precision $epsilon. If invocant is a Inf, -Inf, or a NaN, converts them to a FatRat with 0 denominator and 1, -1, or 0 numerator, respectively.
Type Graph
Num
Routines supplied by role Real
Num 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
Routines supplied by role Numeric
Num does role Numeric, which provides the following routines:
(Numeric) method Numeric
Defined as:
multi method Numeric(Numeric: --> Numeric)multi method Numeric(Numeric: --> Numeric)
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.
(Numeric) method Int
method Int(Numeric: --> Int)
If this Numeric is equivalent to a Real, return the equivalent of calling truncate on that Real to get an Int. Fail with X::Numeric::Real otherwise.
(Numeric) method Rat
method Rat(Numeric: Real = 1.0e-6 --> Rat)
If this Numeric is equivalent to a Real, return a Rat which is within $epsilon of that Real's value. Fail with X::Numeric::Real otherwise.
(Numeric) method Num
method Num(Numeric: --> Num)
If this Numeric is equivalent to a Real, return that Real as a Num as accurately as is possible. Fail with X::Numeric::Real otherwise.
(Numeric) method narrow
method narrow(Numeric --> Numeric)
Returns the number converted to the narrowest type that can hold it without loss of precision.
say (4.0 + 0i).narrow.perl; # OUTPUT: «4»say (4.0 + 0i).narrow.^name; # OUTPUT: «Int»
(Numeric) method ACCEPTS
multi method ACCEPTS(Numeric: )
Returns True if $other can be coerced to Numeric and is numerically equal to the invocant (or both evaluate to NaN).
(Numeric) routine log
multi sub log(Numeric, Numeric = e --> Numeric)multi method log(Numeric: Numeric = e --> Numeric)
Calculates the logarithm to base $base. Defaults to the natural logarithm. Returns NaN if $base is negative. Throws an exception if $base is 1.
(Numeric) routine log10
multi sub log10(Numeric --> Numeric)multi method log10(Numeric: --> Numeric)
Calculates the logarithm to base 10. Returns NaN for negative arguments and -Inf for 0.
(Numeric) routine exp
multi sub exp(Numeric, Numeric = e --> Numeric)multi method exp(Numeric: Numeric = e --> Numeric)
Returns $base to the power of the number, or e to the power of the number if called without a second argument.
(Numeric) method roots
multi method roots(Numeric: Int --> Positional)
Returns a list of the $n complex roots, which evaluate to the original number when raised to the $nth power.
(Numeric) routine abs
multi sub abs(Numeric --> Real)multi method abs(Numeric: --> Real)
Returns the absolute value of the number.
(Numeric) routine sqrt
multi sub sqrt(Numeric --> Numeric)multi method sqrt(Numeric --> Numeric)
Returns a square root of the number. For real numbers the positive square root is returned.
On negative real numbers, sqrt returns NaN rather than a complex number, in order to not confuse people who are not familiar with complex arithmetic. If you want to calculate complex square roots, coerce to Complex first, or use the roots method.
(Numeric) method conj
multi method conj(Numeric --> Numeric)
Returns the complex conjugate of the number. Returns the number itself for real numbers.
(Numeric) method Bool
multi method Bool(Numeric:)
Returns False if the number is equivalent to zero, and True otherwise.
(Numeric) method succ
method succ(Numeric:)
Returns the number incremented by one (successor).
(Numeric) method pred
method pred(Numeric:)
Returns the number decremented by one (predecessor).
Routines supplied by class Cool
Num 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