Could you just tell me what the "for" is when you call the subroutine in the main program? I have seen "for" only in the context of a for loop where you also supply the 3 parameters like initial index, final, and increment.

Sure.

If there are multiple matches in the haystack, the subroutine will return a list of start positions, one for each match.

By giving that list to for, it will execute the print substr statement for each position returned; with $_ taking on each of those start positions one after the other.

Hence, this 

$hay = 'aacctgacctacgtttgacgatcgtacgtcagtcctccgtgctaactgacgtaaaaaaaata
+cgtcccccccc';
$nee = 'acgtacgt';

print substr( $hay, $_-5, length( $nee ) + 10 ) for fuzzyMatch( \$hay,
+ \$nee, 3 );

[download]

prints the 10 matches (+the 5 bytes before and after): 

acctgacctacgtttgac
gacctacgtttgacgatc
gtttgacgatcgtacgtc
gacgatcgtacgtcagtc
atcgtacgtcagtcctcc
gtcagtcctccgtgctaa
tgctaactgacgtaaaaa
aactgacgtaaaaaaaat
aaaaaaaatacgtccccc
aaaatacgtcccccccc

[download]
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In reply to Re^9: Comparing 2 different-sized strings by BrowserUk
in thread Comparing 2 different-sized strings by AdrianJ217

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