count the maximum no.of occurence

[sarvan]

Hi there,

I have program which compares elements of an array with the sentence and prints if it finds the matching.

I m not only comparing single element rather 3 elements at a time.

$str1='It is a guide to action which ensures that the military always 
+obey the commands of the party.'; chomp($str1);
$str2='It is a guide to action that ensures that the military will for
+ever heed Party commands is a guide.'; chomp($str2);

@arr1=split(/\s+/, $str1);
 $n=0;
for($i=0; $i<$#arr1;$i++) {
        $t1="$arr1[$i] $arr1[$i+1] $arr1[$i+2]";
        if($str2=~/$t1/) {
                print "$t1\12";
$n++;
        }
}
print "\n No of matching is : $n";

The output is:

It is a
is a guide
a guide to
guide to action
ensures that the
that the military
 
No of matching is : 6.

What i wanted is, when the three elements from $str1 i.e "is a guide" compared with $str2, it should find two matches, but now it outputs only 1 match. Also i want to count no.of matches for each combination. I.e in this case the countOF(is a guide) is equal to 2. Any suggestion..

[jwkrahn]

You need something like this:

use warnings;
use strict;

my $str1 = q/It is a guide to action which ensures that the military a
+lways obey the commands of the party./;
my $str2 = q/It is a guide to action that ensures that the military wi
+ll forever heed Party commands is a guide./;

my $n = 0;
while ( $str1 =~ /(?=(\S+\s+\S+\s+\S+))/g ) {
    my $t1 = $1;
    while ( $str2 =~ /($t1)/g ) {
        print $1;
        $n++;
        }
    }

print "No of matching is : $n";

[sarvan]

use warnings;
use strict;

my $str1 = q/It is a guide to action which ensures that the military a
+lways obey the commands of the party./;
my $str2 = q/It is a guide to action that ensures that the military wi
+ll forever heed Party commands is a guide./;

my $n = 0;
while ( $str1 =~ /(?=(\S+\s+\S+\s+\S+))/g ) {
    my $t1 = $1;
    while ( $str2 =~ /($t1)/g ) {
        print $1;
        $n++;
        }
    }

print "No of matching is : $n";

but output of the above code comes like this:

It is at is ais a guideis a guides a guides a guidea guide toguide to actionuide to actionide to actionde to actione to actionensures that thensures that thesures that theures that theres that thees that thes that thethat the militaryhat the militaryat the militaryt the military

Not the expected output.. What i expected is:

It is a
is a guide
is a guide
a guide to
guide to action
ensures that the
that the military

And the maximum reference count of each word i want.. i.e in this case. "is a guide" is matched two times so its count is 2. Any suggestions.

[jwkrahn]

Sorry, you need to add newlines, like so:

use warnings;
use strict;

my $str1 = q/It is a guide to action which ensures that the military a
+lways obey the commands of the party./;
my $str2 = q/It is a guide to action that ensures that the military wi
+ll forever heed Party commands is a guide./;

my $n = 0;
while ( $str1 =~ /(?=(\S+\s+\S+\s+\S+))/g ) {
    my $t1 = $1;
    while ( $str2 =~ /($t1)/g ) {
        print "$1\n";
        $n++;
        }
    }

print "No of matching is : $n\n";

[wind]

You're almost there, you simply need to count instead of simply checking for existance:

perlfaq4 - How can I count the number of occurrences of a substring within a string?

[remiah]

I am reading perlretut, and g modifier and zero width look ahead assertion(?=) is what I am reading now... This is good example for me.

use warnings;
use strict;

my $str1 = q/It is a guide to action which ensures that the military a
+lways obey the commands of the party./;
my $str2 = q/It is a guide to action that ensures that the military wi
+ll forever heed Party commands is a guide./;

my $n=0;

while ( $str1 =~ /(?=(\S+\s+\S+\s+\S+))/g ) {
#while ( $str1 =~ /(\S+\s+\S+\s+\S+)/g ) { 
    my $t1 = $1;
    my $line="";

    while ( $str2 =~ /($t1)/g ) {
        $line .= $line eq '' ? '' : ',';
        $line.="str=$t1, $1($-[0])";
        $n++;
    }
    print "$line\n" if $str2 =~/$t1/;
}

print "No of matching is : $n\n";