CODEWITHSUNDEEP
arraysperl
Leon WANG
Leon WANG

Reputation: 103

How to determine multi-array size in PERL?

I created a 2d(mxn) array,@ary_2d, which is used to read different values from different files. Thus, the m and n values keep changing. It is very hard to determine the scalar because each file has different data set, especially for different m values. How can I determine m and n in a simple way? For 1d array, let's say @ary_1d, I can decide it using $#ary_1d. How can I decide the m and n values in the similar way? Any suggestion or easier way would be highly appreciated. Let's see an example below.

my @ary_2d=([12,13,14,15],[67,68,69,70,71]); # row 1: [12,13,14,15] with 4 elements/columns; row 2: [67,68,69,70,71] with 5 elements/columns

in 1d array, like @ary_1d, we can use $#ary_id to get the size of this array. However, how can we get the m value (row value) when we handle 2 or higher dimension arrays? Any simple and clear command would be highly appreciated.

Best, Leon

Upvotes: 1

Views: 636

Answers (2)

choroba
choroba

Reputation: 241828

$#array gives you the index of the last element, the size is in fact $#array + 1 or scalar @array (or @array in scalar context). To get the size of a nested array, use dereference:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my @ary_2d=([12,13,14,15],[67,68,69,70,71]);

my $size = @ary_2d;
print "m: $size\n";

print "n: ", scalar @$_, "\n" for @ary_2d;

Upvotes: 1

Hynek -Pichi- Vychodil
Hynek -Pichi- Vychodil

Reputation: 26121

use List::Util qw( max );
my @ary_2d=([12,13,14,15],[67,68,69,70,71]);
printf "%dx%d\n", 0+@ary_2d, max map 0+@$_, @ary_2d;

Upvotes: 1

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