CPAN Module List::Uniq
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README

NAME
    List::Uniq - extract the unique elements of a list

SYNOPSIS
      use List::Uniq ':all';

      @uniq = uniq(@list);

      $list = [ qw|foo bar baz foo| ];
      $uniq = uniq($list);

DESCRIPTION
    List::Uniq extracts the unique elements of a list. This is a commonly
    re-written (or at least re-looked-up) idiom in Perl programs.

FUNCTIONS
  uniq( { OPTIONS }, ele1, ele2, ..., eleN )
    uniq() takes a list of elements and returns the unique elements of the
    list. Each element may be a scalar value or a reference to a list.

    If the first element is a hash reference it is taken to be a set of
    options that alter the way in which the unique filter is applied. The
    keys of the option set are:

    *   sort

        If set to a true value, the unique elements of the list will be
        returned sorted. Perl's default sort will be used unless the compare
        option is also passed.

        sort defaults to false.

    *   flatten

        If set to a true value, array references in the list will be
        recursively flattened, such that

          ( 'foo', [ [ 'bar' ] ], [ [ [ 'baz', 'quux' ] ] ] )

        becomes

          ( 'foo', 'bar', 'baz', 'quux' )

        flatten defaults to true.

    *   compare

        A code reference that will be used to sort the elements of the list
        if the sort option is set. Passing a non-coderef will cause uniq to
        throw an exception.

        The code ref will be passed a pair of list elements to be compared
        and should return the same values as the cmp operator.

        Using a custom sort slows things down because the sort routine will
        be outside of the List::Uniq package. This requires that the pairs
        to be compared be passed as parameters to the sort routine, not set
        as package globals (see "sort" in perlfunc). If speed is a concern,
        you are better off sorting the return of uniq yourself.

    The return value is a list of the unique elements if called in list
    context or a reference to a list of unique elements if called in scalar
    context.

EXAMPLES
EXPORTS
    Nothing by default.

    Optionally the uniq function.

    Everything with the :all tag.

SEE ALSO
    If you want to unique a list as you insert into it, see Array::Unique by
    Gabor Szabo.

    This module was written out of a need to unique an array that was
    auto-vivified and thus not easily tied to Array::Unique.

AUTHOR
    James FitzGibbon <james+perl@nadt.net>

CREDITS
    The idioms used to unique lists are taken from recipe 4.7 in the *Perl
    Cookbook, 2e.*, published by O'Reilly and Associates and from the Perl
    FAQ section 5.4.

    I pretty much just glued it together in a way that I find easy to use.
    Hopefully you do too.

COPYRIGHT
    Copyright (c) 2004-2008 Primus Telecommunications Canada Inc.

    Copyright (c) 2008-2010 James FitzGibbon

    All Rights Reserved.

    This library is free software; you may use it under the same terms as
    perl itself.