in reply to Replacing nth occurrence of string

Hi,
#!/usr/bin/perl -w
use strict;
my $delimiter = ';';
my $nth = 3;
my $regex = '^(' . ".*$delimiter"x$nth . ')';

while (<DATA>) {
  s/$regex/$1$delimiter/ && print;
}

__DATA__
col1;col2;col3;col4
aaa;bbb;ccc;ddd
AAA;BBB;CCC;DDD

[download]

Output is then: 
col1;col2;col3;;col4
aaa;bbb;ccc;;ddd
AAA;BBB;CCC;;DDD

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Regards,
svenXY

Replies are listed 'Best First'.
Re^2: Replacing nth occurrence of string
by halley (Prior) on Sep 23, 2005 at 15:24 UTC
    When assembling regular expressions, beware: if $delimiter had any regex special characters, you would have to use \Q$delimiter\E in the assembled regex. 
    my $delimiter = '.';
my $nth = 3;
my $regex = '^(' .
            ('.*\Q' . $delimiter . '\E') x $nth .
            ')';

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    --
    [ e d @ h a l l e y . c c ]

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