merging anonymous arrays

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

In a nutshell...

my @a = qw/A B C D E F G H/;
my @b = qw/7 6 5 4 3 2 1 0/;
    
my @KEY = map {$a[$_], $b[$_]} (0 ..  $#a);
[download]

How can I get rid of @a and @b by using anonymous arrays? I think I recall seeing a bit of code around here that pulls it off, or at least discusses it, but my search fu is broken.

Of worthy note:
The size of @a and @b is guaranteed to be the same size.
Can't use hashes, I need to preserve their order.
The size of each array is never more than 32ish or thereabouts.

Comment on merging anonymous arrays Download Code

Replies are listed 'Best First'.
Re: merging anonymous arrays by davido (Cardinal) on Nov 16, 2012 at 08:29 UTC
Your existing code is but one layer of indirection away from wielding anonymous arrays: `my $a_ref = [ qw/ A B C D E F G H / ]; my $b_ref = [ qw/ 7 6 5 4 3 2 1 0 / ]; my @KEY = map { $a_ref->[$_], $b_ref->[$_] } 0 .. $#{$a_ref};` [download] Similar functionality also exists in List::MoreUtils with the "`zip`" and "`mesh`" functions (they're synonymous). `use List::MoreUtils qw( zip ); my $a_ref = [ qw/ A B C D E F G H / ]; my $b_ref = [ qw/ 7 6 5 4 3 2 1 0 / ]; my @KEY = zip @{$a_ref}, @{$b_ref};` [download] Dave	[reply] [d/l] [select]
Re^2: merging anonymous arrays by choroba (Cardinal) on Nov 16, 2012 at 08:37 UTC
Or, if 'anonymous' means 'not using a name nor reference', you can change it to `my @key = map { [qw/A B C D E F G H/]->[$_], [qw/7 6 5 4 3 2 1 0/]->[$_] } 0 .. 7;` [download] In such a case, you have to specify the size externally, though, since there is no way how to refer to the arrays. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]
Re^3: merging anonymous arrays by johngg (Canon) on Nov 16, 2012 at 13:29 UTC
since there is no way how to refer to the arrays There is if you make them arguments to an on-the-fly subroutine. `$ perl -E ' > @key = sub { > map { $_[ 0 ]->[ $_ ], $_[ 1 ]->[ $_ ] } > 0 .. $#{ $_[ 0 ] } > }->( [ qw{ A B C } ], [ qw{ 1 2 3 } ] ); > say qq{@key};' A 1 B 2 C 3 $` [download] A little less esoteric than ColonelPanic's clever solution ++. Cheers, JohnGG	[reply] [d/l]
Re^4: merging anonymous arrays by ColonelPanic (Friar) on Nov 16, 2012 at 14:24 UTC
Re^3: merging anonymous arrays by ColonelPanic (Friar) on Nov 16, 2012 at 10:33 UTC
There is always a way :) `my @key = map { [qw/A B C D E F G H/]->[$_], [qw/7 6 5 4 3 2 1 0/]->[$_] } 0..open(F,$0)&&($_=join('',<F>))&&/map\s{\s(\[.*?\])/s&& eval"\$#{$1}"; print "@key"; die "Not recommended for production code!!";` [download] When's the last time you used duct tape on a duct? --Larry Wall	[reply] [d/l]
Re^2: merging anonymous arrays by SavannahLion (Pilgrim) on Nov 16, 2012 at 08:36 UTC
Ah Ha! Thank you! And now I can get rid of a and b entirely by going just one step further. I knew I was overlooking something. Kudos.	[reply]
Re: merging anonymous arrays by Kenosis (Priest) on Nov 16, 2012 at 13:52 UTC
And another option: `my $a_ref = [qw/A B C D E F G H/]; my $b_ref = [qw/7 6 5 4 3 2 1 0/]; my @KEY; splice( @KEY, @KEY, 0, $a_ref->[$_], $b_ref->[$_] ) for 0 .. $#{$a_ref +};` [download]	[reply] [d/l]
Re^2: merging anonymous arrays by teamassociated (Sexton) on Nov 16, 2012 at 16:27 UTC
have a look at List::MoreUtils....good stuff for such work.	[reply]


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