arraysperlindexingdata-dumper

Perl - Data::Dumper array - start indexing at 0

When you dump your array with:

use Data::Dumper;
@arr=('a','b','c');
print Dumper @arr;

you get something like this:

$VAR1 = 'a';
$VAR2 = 'b';
$VAR3 = 'c';

Is possible to get something like this:

$VAR0 = 'a';
$VAR1 = 'b';
$VAR2 = 'c';

EDIT:

So far I have end up with this one-liner:

perl -lane 'if ($_=~/VAR([0-9]+) = (.*)/) {print "VAR" . ($1-1) . "=" . $2} else {print $_}'

It works as post processing script which decrement the number after VAR. But as you can see it wont produce correct output when you have element like this:

VAR7=$VAR2->[1];

Can I somehow extend this one-liner?

Solution

  • The Dump method takes an optional second array ref where you can specify the desired variable names in the output:

    my @arr   = ('a', 'b', [qw(d e f)]);
my @names = map "VAR$_", 0 .. $#arr;

print Data::Dumper->Dump(\@arr, \@names);

    Output:

    $VAR0 = 'a';
$VAR1 = 'b';
$VAR2 = [
  'd',
  'e',
  'f'
];

    You might also take a look at Data::Printer. I've never used it, but it seems more oriented to the visual display of data structures.