NAME
String::Utils - Provide some optimized string functions
SYNOPSIS
use String::Utils;
say abbrev(<yes no>).keys.sort; # (n no y ye yes)
say after("foobar","foo"); # bar
say all-same("aaaaaa"); # "a"
say all-same("aaaaba"); # Nil
say all-same(""); # Nil
say around("foobarbaz", "ob", "rb"); # foaz
say before("foobar","bar"); # foo
say between("foobarbaz","foo","baz"); # bar
say between-included("foobarbaz","oo","baz"); # oobarbaz
say chomp-needle("foobarbaz", "baz"); # foobar
say consists-of("aaabbcc", "abc"); # True
say consists-of("aaadbcc", "abc"); # False
say consists-of("", "abc"); # True
dd expand-tab("a\tbb\tccc",4); # "a bb ccc"
say has-marks("foo👩🏽💻bar"); # False
say has-marks("fóöbar"); # True
say is-lowercase("foobar"); # True
say is-lowercase("FooBar"); # False
say is-lowercase(""); # True
say is-sha1 "foo bar baz"; # False
say is-uppercase("FOOBAR"); # True
say is-uppercase("FooBar"); # False
say is-uppercase(""); # True
say is-whitespace("\t \n"); # True
say is-whitespace("\ta\n"); # False
say is-whitespace(""); # True
dd leading-whitespace(" \t foo"); # " \t "
say leaf <zip.txt zop.txt ff.txt>; # .txt
say letters("//foo:bar"); # foobar
say ngram "foobar", 3; # foo oob oba bar
say nomark("élève"); # eleve
say non-word "foobar"; # False
say non-word "foo/bar"; # True
.say for paragraphs("a\n\nb"); # 0 => a2 => b
.say for paragraphs($path.IO.lines); # …
my $string = "foo";
my $regex = regexify($string, :ignorecase);
say "FOOBAR" ~~ $regex; # ｢FOO｣
say root <abcd abce abde>; # ab
say sha1("foo bar baz"; # C7567E8B39E...
say stem "foo.tar.gz"; # foo
say stem "foo.tar.gz", 1; # foo.tar
say text-from-url $url, :verbose; # ...
dd trailing-whitespace("bar \t "); # " \t "
say word-at("foo bar baz", 5); # (4 3 1)
use String::Utils <before after>; # only import "before" and "after"
DESCRIPTION
String::Utils provides some simple string functions that are not (yet) provided by the core Raku Programming Language.
These functions are implemented without using regexes for speed.
SELECTIVE IMPORTING
use String::Utils <before after>; # only import "before" and "after"
By default all utility functions are exported. But you can limit this to the functions you actually need by specifying the names in the use statement.
To prevent name collisions and/or import any subroutine with a more memorable name, one can use the "original-name:known-as" syntax. A semi-colon in a specified string indicates the name by which the subroutine is known in this distribution, followed by the name with which it will be known in the lexical context in which the use command is executed.
use String::Utils <root:common-start>; # import "root" as "common-start"
say common-start <abcd abce abde>; # ab
SUBROUTINES
abbrev
say abbrev(<yes no>).keys.sort; # (n no y ye yes)
say abbrev(<foo bar baz>).keys.sort; # (bar baz f fo foo)
Takes 0 or more strings as arguments, and returns a Map with all shortest possible unambigious versions of the given strings as keys, and their associated original string as the value.
Inspired by Text::Abbrev module by KamilaBorowska.
after
say after("foobar","foo"); # bar
say "foobar".&after("foo"); # bar
say after("foobar","goo"); # Nil
Return the string after a given string, or Nil if the given string could not be found. The equivalent of the stringification of / <?after foo> .* /.
all-same
say all-same("aaaaaa"); # "a"
say all-same("aaaaba"); # Nil
say all-same(""); # Nil
If the given string consists of a single character, returns that character. Else returns Nil.
around
say around("foobarbaz","ob","rb"); # foaz
say "foobarbaz".&around("ob","rb"); # foaz
say around("foobarbaz","goo","baz"); # foobarbaz
Return the string around two given strings, or the string itself if either of the bounding strings could not be found. The equivalent of .subst: / <?after ob> .*? <?before rb> /.
before
say before("foobar","bar"); # foo
say "foobar".&before("bar"); # foo
say before("foobar","baz"); # Nil
Return the string before a given string, or Nil if the given string could not be found. The equivalent of the stringification of / .*? <?before bar> /.
between
say between("foobarbaz","foo","baz"); # bar
say "foobarbaz".&between("foo","baz"); # bar
say between("foobarbaz","goo","baz"); # Nil
Return the string between two given strings, or Nil if either of the bounding strings could not be found. The equivalent of the stringification of / <?after foo> .*? <?before baz> /.
between-included
say between-included("foobarbaz","oo","baz"); # oobarbaz
say "foobarbaz".&between-included("oo","baz"); # oobarbaz
say between-included("foobarbaz","goo","baz"); # Nil
Return the string between two given strings including the given strings, or Nil if either of the bounding strings could not be found. The equivalent of the stringification of / o .*? baz /.
chomp-needle
say chomp-needle("foobarbaz","baz"); # foobar
say "foobarbaz".&chomp-needle("baz"); # foobar
say chomp-needle("foobarbaz","bar"); # foobarbaz
Return the string without the given target string at the end, or the string itself if the target string is not at the end. The equivalent of .subst(/ baz $/).
consists-of
say consists-of("aaabbcc", "abc"); # True
say consists-of("aaadbcc", "abc"); # False
say consists-of("", "abc"); # True
Returns a Bool indicating whether the string given as the first positional argument only consists of characters given as the second positional argument, or is empty.
describe-Version
say $*VM.version; # v2025.06.5.gb.1.c.74.b.8.d.8
say describe-Version($*VM.version); # 2025.06-5-gb1c74b8d8
The describe-Version subroutine takes a Version object and returns a string in the "git describe" format.
expand-tab
dd expand-tab("a\tbb\tccc",4); # "a bb ccc"
Expand any tabs in a string (the first argument) to the given tab width (the second argument). If there are no tabs, then the given string will be returned unaltered.
If the tab width is zero or negative, will remove any tabs from the string. If the tab width is one, then all tabs will be replaced by spaces.
has-marks
say has-marks("foo👩🏽💻bar"); # False
say has-marks("fóöbar"); # True
Returns a Bool indicating whether the given string contains any alphanumeric characters with marks (accents).
is-lowercase
say is-lowercase("foobar"); # True
say is-lowercase("FooBar"); # False
say is-lowercase(""); # True
Returns a Bool indicating whether the string consists of just lowercase characters, or is empty.
is-sha1
say is-sha1 "abcd abce abde"; # False
say is-sha1 "356A192B7913B04C54574D18C28D46E6395428AB"; # True
Return a Bool indicating whether the given string is a SHA1 string (40 chars and only containing 0123456789ABCDEF).
is-uppercase
say is-uppercase("FOOBAR"); # True
say is-uppercase("FooBar"); # False
say is-uppercase(""); # True
Returns a Bool indicating whether the string consists of just uppercase characters, or is empty.
is-whitespace
say is-whitespace("\t \n"); # True
say is-whitespace("\ta\n"); # False
say is-whitespace(""); # True
Returns a Bool indicating whether the string consists of just whitespace characters, or is empty.
leading-whitespace
dd leading-whitespace("foo"); # ""
dd leading-whitespace(" \t foo"); # " \t "
dd leading-whitespace(" \t "); # " \t "
Returns a Str containing any leading whitespace of the given string.
leaf
say leaf <zip.txt zop.txt ff.txt>; # .txt
Return the common end of the given strings, or the empty string if no common string could be found. See also root.
letters
say letters("//foo:bar"); # foobar
Returns all of the alphanumeric characters in the given string as a string.
ngram
say ngram "foobar", 3; # foo oob oba bar
say ngram "foobar", 4, :partial; # foob ooba obar bar ar r
Return a sequence of substrings of the given size, while only moving up one position at a time in the original string. Optionally takes a :partial flag to also produce incomplete substrings at the end of the sequence.
nomark
say nomark("élève"); # eleve
Returns the given string with any diacritcs removed.
non-word
say non-word "foobar"; # False
say non-word "foo/bar"; # True
Returns a Bool indicating whether the string contained any non-word characters.
paragraphs
.say for paragraphs($path.IO.lines); # …
.say for paragraphs("a\n\nb"); # 0 => a2 => b
.say for paragraphs("a\n\nb", 1); # 1 => a3 => b
Lazily produces a Seq of Pairs with paragraphs from a Seq or string in which the key is the line number where the paragraph starts, and the value is the paragraph (without last trailing newline).
The optional second argument can be used to indicate the ordinal number of the first line in the string.
my class A is Pair { }
.say for paragraphs("a\n\nb", 1, :Pair(A)); # 1 => a3 => b
Also takes an optional named argument :Pair that indicates the class with which the objects should be created. This defailts to the core Pair class.
regexify
my $string = "foo";
my $regex = regexify($string, :ignorecase);
say "FOOBAR" ~~ $regex; # ｢FOO｣
Produce a Regex object from a given string and modifiers. Note that this is similar to the / <$string> / syntax. But opposed to that syntax, which interpolates the contents of the string each time the regex is executed, the Regex object returned by regexify is immutable.
The following modifiers are supported:
i / ignorecase
# accept haystack if "bar" is found, regardless of case
my $regex = regexify("bar", :i); # or :ignorecase
Allow characters to match even if they are of mixed case.
smartcase
# accept haystack if "bar" is found, regardless of case
my &anycase = regexify("bar", :smartcase);
# accept haystack if "Bar" is found
my &exactcase = regexify("Bar", :smartcase);
If the needle is a string and does not contain any uppercase characters, then ignorecase semantics will be assumed.
# accept haystack if "bar" is found, regardless of any accents
my &anycase = regexify("bar", :m); # or :ignoremark
Allow characters to match even if they have accents (or not).
smartmark
# accept haystack if "bar" is found, regardless of any accents
my &anymark = regexify("bar", :smartmark);
# accept haystack if "bår" is found
my &exactmark = regexify("bår", :smartmark);
If the needle is a string and does not contain any characters with accents, then ignoremark semantics will be assumed.
root
say root <abcd abce abde>; # ab
Return the common beginning of the given strings, or the empty string if no common string could be found. See also leaf.
sha1
say sha1("foo bar baz"; # C7567E8B39E2428E38BF9C9226AC68DE4C67DC39
Returns a SHA1 of the given string. It should only be used for simple identification uses, as it can no longer reliably serve in any cryptographic use.
stem
say stem "foo.tar.gz"; # foo
say stem "foo.tar.gz", 1; # foo.tar
say stem "foo.tar.gz", *; # foo
Return the stem of a string with all of its extensions removed. Optionally accepts a second argument indicating the number of extensions to be removed. This may be * (aka Whatever) to indicate to remove all extensions.
text-from-url
my $text = text-from-url $url, :verbose;
Returns the text found at the given URL, or Nil if the fetch of the text failed for some reason. Takes an optional :verbose named argument: if specified with a trueish value, will show any error output that was received on STDERR: defaults to False, to quietly just return Nil on error.
Assumes the curl command-line program is installed and a network connection is available.
trailing-whitespace
dd trailing-whitespace("bar"); # ""
dd trailing-whitespace("bar \t "); # " \t "
dd trailing-whitespace(" \t "); # " \t "
Returns a Str containing any trailing whitespace of the given string.
word-at
say word-at("foo bar baz", 5); # (4 3 1)
Returns a List with the start position, the number of characters of the word, and the ordinal number of the word found in the given string at the given position, or directly before it (using .words semantics).
Returns Empty if no word could be found at the given position, or the position was out of range.
AUTHOR
Elizabeth Mattijsen liz@raku.rocks
Source can be located at: https://github.com/lizmat/String-Utils . Comments and Pull Requests are welcome.
If you like this module, or what I’m doing more generally, committing to a small sponsorship would mean a great deal to me!
COPYRIGHT AND LICENSE
Copyright 2022, 2023, 2024, 2025 Elizabeth Mattijsen
This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.