Season's greetings fellow monks!
I have a string in the format of:
$str='...............................GAGAACATTAGTGGGTGCAGCGCACAAGCATGG
+CACATGTATACGTATGTAA..................';

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which basically has only A,C,T,G and . inside.
What I want to do is find the rightmost position of the string that has a letter. I tried:
$rightmost_position_of_letter = rindex ($str,[A|T|C|G]);

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and 
$rightmost_position_of_letter = rindex ($str,[ATCG]);

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but gives me -1. What am I doing wrong?

In reply to Proper usage of rindex function? by Anonymous Monk

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