I'm writing a script where I need to take rows of data and turn them into columns. A hash of arrays seemed like the obvious data structure to use, however I am having some problems getting the data back out.

Here is the problem snippet of code:

foreach $head (keys %hoa) {
    my @data = @{$hoa{$head}};
    $item = shift(@data);
    print OUTFILE "$item";
    print OUTFILE ",";
}

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This dies with the error "Use of uninitialized value in string at..." and gives the line number of the line with the shift command. However, if I comment out the next line, the print of $item, the script seems to run just fine. If I print @data, that seems to work fine too. I've read the other nodes of for more info on hashes or arrays and I'm stumped.

One other thing I should mention: I've been writing Perl scripts that run on Unix and Mac OSX for a while. This is the first one I've tried writing to run on Windows. I've already run into a few minor yet irritating differences. I'm not sure if this is one of them or not, but if it matters I'm trying to run this under ActivePerl 5.8.8

In reply to Hash of arrays.. can't shift on derefferenced array by esddew

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