How to populate multidimensional array in Perl?

Question

I'm getting a Use of uninitialized value error. I don't know if I'm populating my multidimensional array correctly.

my @matrix;

for (my $i=1; $i<=3;$i++){
    $matrix[$i][0] = 4;
}
for (my $j=1; $j<=3;$j++){
    $matrix[0][$j] = 4;
}

print $matrix[0][0];

I don't understand why this doesn't work. The way I wrote it, the matrix is supposed to populate like so:

use Data::Dumper; print Dumper \@matrix; Please check perldoc.perl.org/perldsc.html#ARRAYS-OF-ARRAYS — mpapec
– mpapec, Commented Jul 9, 2015 at 21:38
PS, for my $i (1..3) is far cleaner and more efficient than for (my $i=1; $i<=3;$i++) — ikegami
– ikegami, Commented Jul 9, 2015 at 22:18

Jim Davis · Accepted Answer · 2015-07-09 21:44:15Z

3

You're populating $matrix[1][0] and $matrix[0][1], but you don't store anything in $matrix[0][0].

answered Jul 9, 2015 at 21:44

Jim Davis

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Comments

KeepCalmAndCarryOn · Accepted Answer · 2015-07-09 21:39:46Z

1

Perl arrays start at 0 - try

my $i = 0

answered Jul 9, 2015 at 21:39

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