I've been staring at the screen for too long..

It's funny you say it doesn't merge, I've just copied the code from the post and used Data::Dumper to dump $arr at the end and I can see it merged as it should be..

No, the initial position of the member doesn't matter. If we look at an arbitrary first row of two arrefs:

$a->[0] = [qw/f0 f1 f2 f3/];
$b->[0] = [qw/e0 f2 e1 f0 e2];

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If the value of the field in $b->[0] matches one already present in $a->[0] then all values in the matching field in the $b->1..$ arrays should be set in the already matched field. So the final array would be like: 
$m = [
[qw/f0 f1 f2 f3 e0 e1 e2],
[qw/a0 a1 a2 a3 "" "" ""/],# ..and so on all of $a
[qw/b3 "" b1 "" b0 b2 b4/],# ..and so on for $b->[1..$]

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a0,1,2.. being the first,second,third element of a $a->[x] array and likewise for the b0,1,2 of the $b->[x] array.

Does this make it any clearer?

In reply to Re^3: Merging two array(refs) by kpiti
in thread Merging two array(refs) by kpiti

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