peppiv has asked for the wisdom of the Perl Monks concerning the following question:

Yesterday I posted a question about getting data from an array and I was given an excellent answer by broquaint. I'm trying to get particular data from an array and he suggested using a hash, which works perfectly because now I can get other data from the hash when I need. However, I came across an unexpected result.

my %hash = map { chomp; split /,/ } <DATA>;
print $hash{1006},$/;

__DATA__
1001,choochoo
1002,candycane
1003,sockpuppet
1004,choochoo
1005,candycane
1006,sockpuppet6
1007,foo
1008,bar

[download]
Works great! However, some of the data is actually set up like this:
__DATA__
0001,choochoo
0002,candycane
0003,sockpuppet
0109,choochoo

[download]
This doesn't work with references that start with '0'. In fact the '0109' even gives the 'illegal octal digit' warning.

Can anyone shed some light on this? Possible workarounds? I can't change the way I receive the data. The "000's" are what I get.

peppiv

Replies are listed 'Best First'.
Re: Hash references and illegal octal digits
by Mr. Muskrat (Canon) on Dec 24, 2002 at 15:57 UTC

    It's all in how you attempt to access the hash keys...
    $hash{0109} results in the illegal octal digit warning but $hash{'0109'} does not. And the following works fine.

    #!/usr/bin/perl
use strict;
use warnings;

my %hash = map { chomp; split /,/ } <DATA>;
for (sort keys %hash) { print "$_ => $hash{$_}",$/; }

__DATA__
1001,choochoo
1002,candycane
1003,sockpuppet
1004,choochoo
1005,candycane
1006,sockpuppet6
1007,foo
1008,bar
0001,choochoo
0002,candycane
0003,sockpuppet
0109,choochoo

    [download]

    Update: Doh! I forgot to tell you why! You see Perl treats all numbers that start with a 0 as octal (unless the 0 is followed by an x in which case it is treated as hexadecimal).

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      Ah, yes. You is the genius!

      Works great mon!

      Supa Thanx,

      and Happy Holidays!

      peppiv

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        Oops! One more breakdown. It appears the code 
        my %hash = map { chomp; split /,/ } @array;

        [download]
        doesn't play well with this data.

        __DATA__
1001,choochoo
1002,candycane
1003,sockpuppet
1004,choochoo
1005,candycane
1006,sockpuppet6
1007,
1008,bar
0001,choochoo
0002,candycane
0003,sockpuppet
0109,choochoo

        [download]

        Where 1007 doesn't have any value. I have no idea how to treat this. Does anyone have any ideas?

        peppiv

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