Contextual/categorical Histogram

f77coder has asked for the wisdom of the Perl Monks concerning the following question:

Hello, I would like to create a contextual/categorical histogram. I've looked at Histogram and others but them see to be only numeric.

I'm thinking here's the pseudo code but I'm getting confused on keys, hashes and arrays.

My input is grabbing line by line from a file, there are M columns

1. split the line into my @array=split @colref ?

2. shove results from 1 into a hash? my %hash= @array?

3. count duplicate items ? $counts{$_}++ for @my_array;

4. add counts to keys in hash? ;

5. get next line

6 check if key exists?

7 if key exists, increment count

else add new key

next line

example array

use Data::Dumper;
$Data::Dumper::Sortkeys=1;
my @my_array=('a','-2','3','b','0xffff','c','2','b','a','4','a','a','2
+00');
my %counts;
$counts{$_}++ for @my_array;
print Dumper(\%counts);
[download]

$VAR1 = {
          '-2' => 1,
          '0xffff' => 1,
          '2' => 1,
          '200' => 1,
          '3' => 1,
          '4' => 1,
          'a' => 4,
          'b' => 2,
          'c' => 1
        };
[download]

Many thanks for any help.

Comment on Contextual/categorical Histogram Select or Download Code

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Re: Contextual/categorical Histogram
by Athanasius (Archbishop) on Aug 03, 2014 at 04:24 UTC

Hello f77coder,

It seems to me that the code you’ve shown is already doing most of what you need. I’ve tweaked it a bit and added some (admittedly naïve¹) code to generate the histogram: