Re^2: rectangularizing input to become array

pack with the A template

The many and various uses of pack. I'm glad to have another useful example. What's the A template?

Code replication between readmore tags, invocation, output, then source.

$ ./1.shiraz.pl 
$raRect = 
            'abcdef',
            'abcdef',
            'abcde ',
            ' bcdef'
          ;
$

#!/usr/bin/perl -w
use 5.011;
use Data::Dumper;

open my $inFH, q{<}, \ <<__EOD__ or die $!;
abcdef
abcdefg
abcde
 bcdefgh
 bcd    
__EOD__

chomp( my @lines = <$inFH> );
close $inFH or die $!;

my $width  = 6;
my $height = 4;

my $raRect = makeRect( \ @lines, $width, $height );

print Data::Dumper->Dumpxs( [ $raRect ], [ qw{ raRect } ] );

sub makeRect
{
    my( $raLines, $width, $height ) = @_;
    my @rect;
    push @rect, pack qq{A$width}, shift @{ $raLines } for 1 .. $height
+;
    return \ @rect;
}
[download]

Can you say a few words about this line of code (I've never seen this before in Data::Dumper)?

print Data::Dumper->Dumpxs( [ $raRect ], [ qw{ raRect } ] );

Thanks.

Comment on Re^2: rectangularizing input to become array Select or Download Code

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Re^3: rectangularizing input to become array by johngg (Canon) on Mar 01, 2019 at 12:41 UTC
Unlike `Dumper()`, `Data::Dumper->Dump()` and `->Dumpxs()` are not exported by Data::Dumper. However, for a little extra effort they do provide clearer output, especially if examining multiple data structures. They allow you to distinguish arrays and references to arrays, ditto for hashes. Many Monks recommend and use the more modern and flexible Data::Dump module but Data::Dumper has the advantage of being in core from way back so is useful if maintaining elderly servers in a closed environment running, say, Perl 5.8 or even earlier. Here is a simple example. Read more... (3 kB) I hope this is helpful. Cheers, JohnGG	[reply] [d/l] [select]
Re^3: rectangularizing input to become array by haukex (Archbishop) on Mar 01, 2019 at 08:43 UTC
What's the A template? As documented in pack, it's a "text (ASCII) string, will be space padded." I showed the differences between some of those `pack` templates here. Can you say a few words about this line of code (I've never seen this before in Data::Dumper)? `print Data::Dumper->Dumpxs( [ $raRect ], [ qw{ raRect } ] );` Simplifying a lot, `Dumpxs` is just another name for `Dump`. (See Where is Data::Dumper->Dumpx?)	[reply] [d/l] [select]