Re^2: adding an index column to a csv data file

[ng0177]

my $i=0;
$_->[2] = $i++ for @multi_array;

works for me too now after resetting $i which masked it.

You are right, the present data set has two columns and the other one three. I should have mentioned that.

Thanks for helping out. The generalisation is useful to have.

[AnomalousMonk]

You could generalize this a bit further and eliminate the  $i variable (one less thing to worry about):

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @multi_array = ([ 99, 88 ],  [ 77, 66 ],  [ 55, 44 ], );
 ;;
 push @{ $multi_array[$_] }, $_ for 0 .. $#multi_array;
 dd \@multi_array;
"
[[99, 88, 0], [77, 66, 1], [55, 44, 2]]

but I'm not sure this is really an improvement WRT clarity and maintainability! unshift or splice could be used to stuff the new element at other offsets in the array. The "pure index" version is even more obscure:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @multi_array = ([ 99, 88 ],  [ 77, 66 ],  [ 55, 44 ], );
 ;;
 $multi_array[$_][ @{$multi_array[$_]} ] = $_ for 0 .. $#multi_array;
 dd \@multi_array;
"
[[99, 88, 0], [77, 66, 1], [55, 44, 2]]

[ng0177]

The $i less variant is good for learning.