If you're going to worry about with and without decimal places (++ for that), try: 

#!/usr/bin/perl

use strict;
use warnings;

use Regexp::Common;

while (<DATA>) {
    s|($RE{num}{decimal})%|$1 * 0.01|eg;
    print;
}

__DATA__
ENSP00000233379 1058 30 1206 1298 96.1% 13 + 96524483 96533474 8992
ENSP00000233379 1058 30 1206 1298 96% 13 + 96524483 96533474 8992

[download]
Ok, so you have to go install Regexp::Common. Getting this right every time is well worth that minor expense, IMO. Otherwise, if somehow the data gets corrupted so there is, say, "S%" in there somewhere, your code will generate an error. To take care of "S6%", just add a \b: 
    s|\b($RE{num}{decimal})%|$1 * 0.01|eg;

[download]
It will leave the corruption alone this way. Detecting the corruption is as simple as checking if there are remaining %'s after the substitution: 
    if (/%/) {
       print STDERR "Input has been corrupted!";
       # die ?
    }

[download]
Ok, maybe I'm going beyond the original post's scope here... ;-)

In reply to Re^2: Converting percentage into number by Tanktalus
in thread Converting percentage into number by uv2007

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