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List-Util-sglice-0.002
River stage one • 1 direct dependent • 1 total dependent
/ List::Util::sglice

NAME

List::Util::sglice - Remove some elements where code returns true

VERSION

This document describes version 0.002 of List::Util::sglice (from Perl distribution List-Util-sglice), released on 2023-09-18.

SYNOPSIS

 use List::Util::sglice qw(sglice);

 my @ary = (1,2,3,4,5,6,7,8,9,10);

 # 1. remove all even numbers (equivalent to: @ary = grep { !($_ % 2 == 0) } @ary

 #                       --------------------------- 1st param: code to match elements to remove
 #                      /     ---------------------- 2nd param: the array
 #                     /     /  -------------------- 3rd param: (optional) how many matching elems to remove, undef means all, negative allowed to mean last N matching elems
 #                    /     /  /
 sglice { $_ % 2 == 0 } @ary    ;  # => (1,3,5,7,9)

 # 3. remove first two even numbers
 sglice { $_ % 2 == 0 } @ary,  2;  # => (1,3,5,6,7,8,9,10)

 # 4. remove last two even numbers
 sglice { $_ % 2 == 0 } @ary, -2;  # => (1,2,3,4,5,6,7,9)

 # 5. remove elements #0..#2, equivalent to: splice @ary, 0, 2
 sglice { $_[1] <= 2  } @ary;      # => (4,5,6,7,8,9,10)

 # 6. put even numbers to the beginning of array
 unshift @ary, sglice { $_ % 2 == 0 } @ary;  # => (2,4,6,8,10,  1,3,5,7,9)

DESCRIPTION

This module provides "sglice".

FUNCTIONS

Not exported by default but exportable.

sglice

Usage:

 sglice CODE ARRAY, NUM_TO_REMOVE
 sglice CODE ARRAY

sglice (mnemonic: "g" is for grep) somewhat resembles splice. Instead of specifying offset and number of elements to remove from ARRAY, you specify CODE to match elements to remove. Unlike splice, sglice does not let you reinsert new items (see List::Util::msplice for that).

In CODE, $_ (as well as $_[0]) is set to array element. $_[1] is set to the index of the element, so you can still remove elements by their position.

The third parameter, NUM_TO_REMOVE, is the number of elements to remove. If unspecified, all matching elements will be removed. You can also specify negative integer to remove NUM last matching elements. Setting this to 0 effectively means a no-op.

In list context, the function returns the removed elements. In scalar context, it returns the last removed elements.

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/List-Util-sglice.

SOURCE

Source repository is at https://github.com/perlancar/perl-List-Util-sglice.

SEE ALSO

List::Util::mapsplice.

splice in perlfunc.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2023 by perlancar <perlancar@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=List-Util-sglice

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.