So I'm working on a quick script that requires me to do some counting. The long and short of it is that I have some strings (generated elsewhere in the script) and I need to know how many newlines (for example) they contain. The canonical response (I've discovered) is to use tr//: 
$count = ($string =~ tr/\n/\n/);

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Well, because there were other things I wanted to count I ended up using a similar construction with s///g (did you know that \s matches \n for m// and s/// but not for tr///? I didn't) which is where I get confused. What do you expect the output from these to be: 
# Greedy
$string = q(xxxx); 
$count = ($string =~ s/x*/#/g); 
print qq($string $count), $/;

# Not greedy
$string = q(xxxx); 
$count = ($string =~ s/x*?/#/g); 
print qq($string $count), $/;

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I expected # 1 and #### 4. I got ## 2 and ######### 9. Excuse me? How's that again? 2 and 9? Color me confused.

Can anyone shed some light on this and maybe help me figure out how I can see what perl's doing to arrive at these numbers?

Note: I did figure out that my confusion stems from using * rather than + as modifier. Using + does give 1 and 4 (greedy vs. not-greedy) above. Whoops :) Even so, I'm still confused about the 2 and 9 from using star....

In reply to Regex (counting) confusion :( by snax

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