http://www.perlmonks.org?node_id=307292


in reply to Re: Re: A regex that does this, but not that?
in thread A regex that does this, but not that?

Well, pg's solution works for the limited input provided and you haven't given any further particulars regarding input. That solution breaks just changing the first word from "thought" to "though" :

my $var = "though test tot 1 2 3 tesset"; $var =~ s/(t.*?t)/($1 ne "test") ? "" : $1/ge; print $var; # prints: esoesset

But, now you mention a further constraint that the words to be deleted may not contain any 't's inside, which is not inferrable from your earlier posts at all. Providing a good specification is much more than providing a sample case (but providing test cases *is* important).

Anyway, here's a go at your new specs:

my $var = <<TT; target blah foo test thought 123 though tempest testament though tightest treatment thermostat tantamount taboo TT $var =~ s/(?!\btest\b)(\bt[^t\W]*t\b)//g; print $var; __END__ ## Result: blah foo test 123 though testament though tightest treatment thermostat tantamount taboo

So, all the 't.*t' words on the second line remain because they contain a 't' character within. All the 't.*t' words on the first line get deleted except for 'test'.