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

HI everyone, I want to count the number of occurence of a number in a text. i know how to do it for a character but not for a number. my data contains - 
0.000000e+00           105         35324
1.000000e+00           105         35324
2.000000e+00           105         33308
3.000000e+00           105         35324
4.000000e+00           105         33308
5.000000e+00           105         35324
6.000000e+00           105         33227
7.000000e+00           105         33011
8.000000e+00           105         33227
9.000000e+00           105         35606
1.000000e+01           105         33227
1.100000e+01           105         35537

[download]

i have to get the number of occurence of the 3rd column.

Thanks

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Re: to count the number of occurence of a number
by bart (Canon) on Sep 28, 2011 at 10:55 UTC
    You mean the frequency of that value? Use the classic word frequency count idiom (a task that is very simple in Perl: use a hash). It's not because it's a number that you cannot treat it as a string. 
    my %frequency;
while(<>) {
    my @column = split ' ' or next;
    $frequency{$column[2]}++;
}

    [download]
    Now you can just print out what you've got. 
    {
    local($\, $,) = ("\n", "\t");  # tab delimited output
    foreach (sort { $frequency{$b} <=> $frequency{$a} || $a <=> $b } k
+eys %frequency) {
        print $_, $frequency{$_};
    }
}

    [download]
    Here's the result I got from your sample: 
    35324    4
33227    3
33308    2
33011    1
35537    1
35606    1

    [download]
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      Hi bart, thanks for ur response, am getting error while compling $frequency requires explicit package.
[reply]
        It's working fine (Perl v5.10.1): 
        #!/usr/bin/perl
use strict;
use warnings;

my %frequency;
while(<DATA>) {
    my @column = split ' ' or next;
    $frequency{$column[2]}++;
}

{
    local($\, $,) = ("\n", "\t");  # tab delimited output
    foreach (sort { $frequency{$b} <=> $frequency{$a} || $a <=> $b } k
+eys %frequency) {
        print $_, $frequency{$_};
    }
}

__DATA__
0.000000e+00           105         35324
1.000000e+00           105         35324
2.000000e+00           105         33308
3.000000e+00           105         35324
4.000000e+00           105         33308
5.000000e+00           105         35324
6.000000e+00           105         33227
7.000000e+00           105         33011
8.000000e+00           105         33227
9.000000e+00           105         35606
1.000000e+01           105         33227
1.100000e+01           105         35537

        [download]

        To get input from a file, see [Re^2: Alphanumeric sort].

        Have a nice day, j

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