merlyn@iwarp.intel.com (Randal L. Schwartz) (04/24/91)
In article <1991Apr23.180034.7349@progress.com>, root@progress (Root of all Evil) writes: | Is there any way within ex (or some other text processing utility) to | access the nth occurrence of a pattern? What I'd like to do is search | a file for the nth occurrence of a pattern and then change that pattern | but no others. I've tried using ex: | | ex -s FILE << QUIT | /STRING1/n s/STRING1/STRING2/ | wq! | QUIT | | but this only places me n lines after the first occurrence of STRING1. | Any ideas? I'd like to avoid writing to a temporary file. perl -pe '/STRING1/ && (++$n == 20) && s/STRING1/STRING2/' <in >out OK, so the syntax is cryptic; do it C-like if you want: perl -pe 'if (/STRING1/ && (++$n == 20)) { s/STRING1/STRING2/; }' <in >out or even (more verbosely): perl -pe 'if (/STRING1/) { s/STRING1/STRING2/ if ++$n == 20; }' <in >out (well, maybe not more verbosely, then... :-) Or even: perl -pe 's/STRING1/STRING2/ if /STRING1/ && (++$n == 20);' <in >out All of these presume "20" is your magic occurance. Season to taste. print "Just another Perl hacker," # Perl is available from all GNU sites... -- /=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\ | on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III | | merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn | \=Cute Quote: "Intel: putting the 'backward' in 'backward compatible'..."====/
merlyn@iwarp.intel.com (Randal L. Schwartz) (04/26/91)
In article <1991Apr25.040751.1991@ttsi.lonestar.org>, root@ttsi (System) writes: | >perl -pe '/STRING1/ && (++$n == 20) && s/STRING1/STRING2/' <in >out | > | >perl -pe 'if (/STRING1/ && (++$n == 20)) { s/STRING1/STRING2/; }' <in >out | > | >perl -pe 'if (/STRING1/) { s/STRING1/STRING2/ if ++$n == 20; }' <in >out | > | >perl -pe 's/STRING1/STRING2/ if /STRING1/ && (++$n == 20);' <in >out | > | >All of these presume "20" is your magic occurance. Season to taste. | > | >print "Just another Perl hacker," # Perl is available from all GNU sites... | | These all presume only one occurrence or first occurrence per line. | Is that the requirement? How would you handle counting multiple | occurrences per line in perl? Thanks for posting the solutions above. OK, now you did it. You asked me to get ugly. Hang on to your hat... perl -pe 's/STRING1/(++$n == 20) ? "STRING2" : $&/ge' <in >out You might need to look at this one for a while to figure out what's happening. Trust me, it'll be good for you. :-) (And if you can't figure it out, I know this great book on the subject... :-) print "Just another Perl hacker,"; -- /=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\ | on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III | | merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn | \=Cute Quote: "Intel: putting the 'backward' in 'backward compatible'..."====/