in reply to Re: naming a variable with the datum from another variable
in thread naming a variable with the datum from another variable

Okay, so that's bad way of doing it, but how do you do it because I have a working program that I just need to add a couple of loops into, and fiddling around with the data structures at this stage could be messy.

However, I would like to learn how to do it properly. I'm using an associative array already so that I can number the columns. Can I put an associative array within another associative array without all the data in them getting jumbled up?

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Re^3: naming a variable with the datum from another variable
by holli (Abbot) on Feb 12, 2005 at 18:02 UTC
    Can I put an associative array within another associative array without all the data in them getting jumbled up?
    Yes. That is a Hash of Hashes, HoH in short. see perlref and perlreftut. In fact you can create any kind of data-structure using perl-hashes and arrays. I donīt know if there is a "deepness"-limit but i doubt that.

    #sample set up a hash of hashes
my %h =
(
    key1 => { subkey11 => subval11, subkey21 => subval21 },
    key2 => { subkey12 => subval12, subkey22 => subval22 },
);

#access it
print $h{key1}->{subkey11};

#loop it
for ( keys %{$hash->{key2}} )
{
    print $hash->{key2}->{$_};
}

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    Update:
    And yes, show us your code. But be sure to strip all non-relevant parts.

    holli, /regexed monk/
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      I donīt know if there is a "deepness"-limit but i doubt that.

      Trust me - if there is, it's very, very large. I've had structures looking like join 'o', ('H') x dozens. 30+ deep. Even perl 5.6 could handle it. (Once they were all objects, perl 5.8 became required - 5.6 would crash.)

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Re^3: naming a variable with the datum from another variable
by Tanktalus (Canon) on Feb 12, 2005 at 17:53 UTC

    I'm not entirely sure what you're trying to do - although here's a guess. It's not using hashes (associative arrays), but it could.

    use Data::Dumper;

my $header = <DATA>;
my @cols_h = split /\t/, $header;

my @data;

while (<DATA>)
{
    chomp;
    my @info = split /\t/;
    push @data, \@info;
}

# uncomment this to see the data we have so far.
#print Dumper(\@data);

foreach (@data)
{
    my $avg = ($_->[2] + $_->[3]) / 2;
    push @$_, $avg
}

# uncomment this to see the data we have so far.
#print Dumper(\@data);

# at this point, each @data is an array of arrays.
# Each of the arrays contained in @data is "anonymous" (unnamed).
# These anonymous arrays have the four columns (0-3), and a fifth colu
+mn
# which is an average of columns 2 and 3 (zero-based).

__DATA__
ID_REF    IDENTIFIER    GSM29783    GSM29784
31307_at    L17325    77    788
31308_at    L17330    -777    -877
31309_r_at    U50277    7    8
31310_at    X52009    -7777    -887
31311_at    X61070    77777    88

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