Hi,

since a week, i'm studying the perlretut. I'm confused with an example:

         while ($dna =~ /(\w\w\w)*?TGA/g) {  # note the minimal *?
            print "Got a TGA stop codon at position ", pos $dna, "\n";
        }

which prints

        Got a TGA stop codon at position 18
        Got a TGA stop codon at position 23

[download]

On the regexp:   /(\w\w\w)*?TGA/g

can anybody explain me step by step the procedure that the regexp engine does with the provided string?

 $dna = "ATCGTTGAATGCAAATGACATGAC"

EDIT:

I was missing the fact that *? matches the empty string too, so even if at the start of the line a TGA is going to be counted. However i still don't understand why this is bugged without \G.

In reply to Understanding a portion on the Perlretut by BlueStarry

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