First off, a couple of style issues:

• If you find yourself writing the same code over and again put it in a sub
• Don't use map in place of for used as a statement modifier

With that somewhat in mind consider the following:

use strict;
use warnings;
use List::Util;

my %candidate = CountWords ('the the the the the the the');
my %reference = CountWords ('the cat is the on the mat');
my %counts =
    map {$_ => List::Util::min ($candidate{$_} || 0, $reference{$_} ||
+ 0)}
    keys %candidate, keys %reference;

print "$_: $counts{$_}\n" for sort keys %counts;


sub CountWords {
    my ($sentence) = @_;
    my @words = split (/\W/, $sentence);
    my %wordCount;

    ++$wordCount{$_} for @words;
    return %wordCount;
}
[download]

Prints:

cat: 0
is: 0
mat: 0
on: 0
the: 3
[download]

for my $key (keys %candidate) {
    print "$key -> ";
    my $cand = $candidate{$key};
    my $ref  = $reference{$key};
    if ($ref and $ref < $cand) {
        print $ref;
    } else {
        print $cand;
    }
    print "\n";
}
[download]

Hi, Thanks for the reply

And here is the doubt. suppose a word in the candidate that is not at all present in the reference, in such case it gives me the count as 1.(since 1 time it appeared in $cand). But, i expect it to be zero. because it dint appear in $ref..

An Example sentences: $candidate="it is not probable that it is the end"; $reference="it is unlikely that it is the end";

It is trivial to change the code I provided to give the expected result (in fact, you did not specify what to do if the term does not occur in the $reference, so I assumed you wanted to see the value from $candidate). Just remove 9 characters and add 5 somewhere :) (YMMW)

Consider:

say scalar split /\W/,  "the cat is the on the mat";       # 7
say scalar split /\W/,  "the  cat  is  the  on  the  mat"; # 13

say scalar split /\W+/, "the cat is the on the mat";       # 7
say scalar split /\W+/, "the  cat  is  the  on  the  mat"; # 7
[download]

#!/usr/bin/perl -w
use strict;

my $candidate = "the the the the the the the";
my $reference = "the cat is the on the mat";

my %cand_histogram;
my %ref_histogram;

$cand_histogram{$_}++ foreach (split(/\s+/,$candidate));
$ref_histogram{$_}++  foreach (split(/\s+/,$reference));

my %seen;
printf "%-6s %-10s %-10s\n", 'Key','Candidate','Reference';
foreach my $key ( sort {
                          $seen{$b} <=> $seen{$a} #descending word cnt
                                   or
                               $a cmp $b       #alphabetic otherwise 
                       }
                  grep {!$seen{$_}++}  # each key just once, 
                                       # but count 'em also!, 
                                       # 2 means => in both hashes
                 (keys %cand_histogram, keys %ref_histogram)
                )
{
   printf "%-6s %-10s %-10s\n", $key,
                                $cand_histogram{$key}||='0',
                                $ref_histogram{$key} ||='0';
}

__END__

OUTPUT:

Key    Candidate  Reference 
the    7          3         
cat    0          1         
is     0          1         
mat    0          1         
on     0          1
[download]

Hi marshall, Thanks for the code..

And one little modification i want to do on that.. Now it gives me all the words in both the candidate and reference and their counts.

But the output i look for is, i want to know only minimum count of candidate words among both candidate and reference..

for e.g if a word "the" appears 7 times in candidate and 2 times in reference. it should be able to get 2 as the min between two counts. like this for all the words in candidate alone..

please give me an idea how to do this. I will try

Thanks...

Hi sarvan,
I think that if you study the code, you will find that you have all that you need. The last "foreach" loop is on the fancy side of things, but it just loops over all of the unique keys in a special sort order. $cand_histogram{$key}||='0' uses 0 as the value in the case that there is no value for $cand_histogram{$key}. The print statement prints the 3 things that you need in order to calculate what you want. Why don't you give some code a try? Post your effort back here after you study it a bit.