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in reply to Error in my Regular expression pattern

perldoc://count occurrences 

perldoc -q " count.*?occurrences "

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

Learn more about the flying lentil operator

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Re^2: Error in my Regular expression pattern
by Anonymous Monk on Mar 18, 2012 at 07:28 UTC
    Like perlop#m/PATTERN/msixpodualgc ( perlop#m// ), says,
    m// in scalar context returns true if it succeeds, false if it fails.

    Each time m// succeeds against a variable, like when  $n = m/twinkle/ig; executes, position is changed, so that  while(/twinkle/ig) { executes, only the second twinkle is counted.

    If you add this to your program before the while loop 

     print "pos is ", pos, ", remainder '", substr($_, pos), "'\n";
pos($_) = undef;

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    this resets pos associated with $_, and then your program will produce 
    Number of occurences = 1
pos is 7, remainder ' twinkle little star'
Found 2 times

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    Like perlfaq4 says, if you want the number of occurances, use the flying lentil operator, use  my $count =()= m/twinkle/ig;

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