in reply to counting inside the loop

$count{$t1}++

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This will have the number of occurences of each combination stored in a hash. Think about how it works and you will know where to put it. If not, try out a few locations and observe what happens. Don't forget to print out the hash after all the loops are finished.

my $count=($str2=~ tr/$t1//);

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This will count how often the characters in $t1 are in $str2, i.e. if $t1 were "ab" it would count all 'a's and 'b's in $str2. Is that really what you want?

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Re^2: counting inside the loop
by AnomalousMonk (Archbishop) on Jun 30, 2011 at 15:09 UTC
    my $count=($str2=~ tr/$t1//);

    This will count how often the characters in $t1 are in $str2 ...

    Unfortunately, the  tr/// operator does not interpolate, but the  s/// or, better yet, the  m// operator can serve here: 

    >perl -wMstrict -le
"my $s = 'foo bar fooo bar foooo bar';
 my $cc = 'foz';
 ;;
 my $count = ($s =~ tr/$cc//);
 print $count;
 ;;
 $count = '$c$c$' =~ tr/$cc//;
 print $count;
 ;;
 $count = $s =~ tr/foz//;
 print $count;
 ;;
 $count = $s =~ s{ ([$cc]) }{$1}xmsg;
 print $count;
 ;;
 $count =()= $s =~ m{ [$cc] }xmsg;
 print $count;
 ;;
 $count = $s =~ s{ [$cc] }{}xmsg;
 print $count;
 print qq{'$s'};
"
0
5
12
12
12
12
' bar  bar  bar'

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    Note: There is no need for a capture group in the  s/// expression if characters in the string can be counted 'destructively':
        $count = $s =~ s{ [$cc] }{}xmsg;

    Update: Added  s/// and  m// examples, discussion.

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Re^2: counting inside the loop
by sarvan (Sexton) on Jul 01, 2011 at 11:09 UTC
    Hi, For this, 
    $count=($str=~ tr/($t1)//);

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    if $t1 has ab. i just want to count how many times ab is their in $str. together. not as seperately 'a' 'b'.

    What can be done for that..
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        Hi, 
        $s='finding related pages finding on the world wide web';
my $count=$s=~ m/finding/g;
print $count;

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        I expect the result as 2.. becus "finding" exists two times in $s. but the output is 1. Why??

        thanks
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