global regex

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Re: global regex by si_lence (Deacon) on Jul 08, 2009 at 13:12 UTC
your code matches the first 'word' and prints it, then goes to the next line. One way of matching all words on a line is `while(<DATA>) { while ( /(\w+)/g ) { print "$1 "; } }` [download] cheers si_lence	[reply] [d/l]
Re: global regex by Transient (Hermit) on Jul 08, 2009 at 13:16 UTC
try `while( <DATA> ) { my @matches = /(\w+)/g; print join( ',', @matches ), "\n"; }` [download] or `while ( <DATA> ) { while ( /(\w+)/g ) { print $1, "\n"; } }` [download] also, you're missing a semicolon after the regexp, but I assume that you just typed that out, and didn't cut and paste =)	[reply] [d/l] [select]
Re: global regex by psini (Deacon) on Jul 08, 2009 at 13:15 UTC
or use match in array context: `while(<DATA>) { my @a=/(\w+)/g; print "@a\n"; } __DATA__ word1 word2 word3 .. .. ..` [download] updates: Typo corrected: s/scalar/array/ thanks to AnomalousMonk Rule One: "Do not act incautiously when confronting a little bald wrinkly smiling man."	[reply] [d/l]
Re: global regex by jethro (Monsignor) on Jul 08, 2009 at 13:26 UTC
The first parentheses is always stored only in $1 with or without the g switch. You can either use `while(<DATA>) { while (1) { last if not /(\w+)/g; print $1,"\n"; } }` [download] or `while(<DATA>) { my @ar= /(\w+)/g; print @ar,"\n"; }` [download] As you can see, the g switch works differently in scalar and array context. Read perlre to get the details. And you might add "use warnings;" to your scripts	[reply] [d/l] [select]
Re: global regex by ww (Archbishop) on Jul 08, 2009 at 13:27 UTC
Several things. $2 and $3 are not populated by simply using `/g` You're not testing for matches Your `__DATA__` section reflects a "log file" which has precisely 3 words per line. Note what happens to line 3 of my `__DATA__`. `#!/usr/bin/perl use strict; use warnings; # 778252 while(<DATA>) { if ( $_ =~ /(\w+\s)(\w+\s)(\w+\s)/ ) { print "$1 $2 $3"; } } __DATA__ word1 word2 word3 word4 word5 word6 7word 12345 8word @- 9word` [download] Output: word1 word2 word3 word4 word5 word6 7word 12345 8word	[reply] [d/l] [select]
Re: global regex by Anonymous Monk on Jul 08, 2009 at 13:37 UTC
but the /g shouldn't make it match the whole string instead stopping after find the first ?	[reply]
Re^2: global regex by ikegami (Patriarch) on Jul 08, 2009 at 14:11 UTC
Depends on context, but yes in this case (assuming your code is simply missing a ";"). It, however, does not affect what gets put in $1, $2, etc. The earliest set of parens goes in $1, the next earliest set of parens goes in $2, etc. Since you only have one set of parens, only $1 will ever get populated.	[reply]
Re: global regex by biohisham (Priest) on Jul 08, 2009 at 14:52 UTC
ok, everybody hammered the nail on its head, here is a bullet of mercy. You're using a loop, but you've got to realize that when this loop iterates over and over it comes on the pattern and the code you wrote over and again: `/(\w+)/g; print "$1";` [download] so, you use only one backreference ($1), that gets populated -from the start-everytime the loop iterates, so what you are doing wrong is assuming that for every file there gotta be separate variables to fill up but the fact is the `while(<DATA>){}` fetches a new DATA item everytime it goes through and replace it in the $1...hope you got the idea....best of luck Excellence is an Endeavor of Persistence. Chance Favors a Prepared Mind	[reply] [d/l] [select]
Re^2: global regex by biohisham (Priest) on Jul 08, 2009 at 16:11 UTC
I thought I will extend my previous reply with this code to show you that $1 is filled up over and over with new DATA... `use strict; use warnings; my $match=0; while(<DATA>){ while(my $text = /Name: *(\w+)/g){ ++$match; print "Match no. $match is $1\n"; } } __DATA__ Name: Alpha Name: Beta Name: Gamma Name: Epsilon Name: Delta` [download] Excellence is an Endeavor of Persistence. Chance Favors a Prepared Mind	[reply] [d/l]