awohld has asked for the wisdom of the Perl Monks concerning the following question:

I have this list that is basically what a List::MoreUtils mesh or zip output of a list would look like.

Looking all over there doesn't seem to be an unmesh or unzip function out there and my attempts look ugly. I know how many list were zipped into the input, so 
my @test1 = qw( 1 1 2 2 3 3 4 4 5 5 6 6 7 7 );
my @test2 = qw( 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 );

#  unzip @test1, we know to make it two lists
my $unzipped = unzip( 2, @test1 );
$unzipped = [
    [ 1, 2, 3, 4, 5, 6, 7 ],
    [ 1, 2, 3, 4, 5, 6, 7 ],
]

#  unzip @test2, we know to make it three lists
my $unzipped = unzip( 3, @test2 );
$unzipped = [
    [ 1, 2, 3, 4, 5, 6, 7 ],
    [ 1, 2, 3, 4, 5, 6, 7 ],
    [ 1, 2, 3, 4, 5, 6, 7 ],
]

[download]
Any ideas if "unzip" or "unmesh" exists or an elegant way to implement unzip?


Replies are listed 'Best First'.
Re: UnMesh or UnZip List
by AnomalousMonk (Archbishop) on Jun 27, 2016 at 22:49 UTC

    List::MoreUtils::part().

    Update: E.g.: 

    c:\@Work\Perl>perl -wMstrict -le
"use List::MoreUtils qw(part);
 ;;
 use Data::Dump qw(dd);
 ;;
 my @test = qw(1 1 2 2 3 3 4 4 5 5 6 6 7 7);
 ;;
 my $i = 0;
 my @unzip = part { $i++ % 2 } @test;
 dd \@unzip;
 ;;
 @test = qw(9 9 9 8 8 8 7 7 7 6 6 6 5 5 5 4 4 4 3 3 3);
 $i = 0;
 @unzip = part { $i++ % 3 } @test;
 dd \@unzip;
"
[[1 .. 7], [1 .. 7]]

[
  [9, 8, 7, 6, 5, 4, 3],
  [9, 8, 7, 6, 5, 4, 3],
  [9, 8, 7, 6, 5, 4, 3],
]

    [download]
    The call to  part() is easily wrapped in a function call.

    Give a man a fish:  <%-{-{-{-<

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