Rewriting Three Regexes as One

arunhorne has asked for the wisdom of the Perl Monks concerning the following question:

Sorry, this is probably a really dumb question but I have this file containing a set of equations. I'm trying to standardise some data sets and so have written a little script to search it using a regex. I want to find all the occurrences of ='s that do not have whitespace on either side. I can do it using the three regular expressions:

m/\S=\S/g
m/ =\S/g
m/\S= /g
[download]

However when I try to combine all of these into one regex as follows it stops working:

m/(\S=\S)|( =\S)|(\S= )/g

I'm sure its a silly error but what am I doing wrong?

Comment on Rewriting Three Regexes as One Select or Download Code

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(jeffa) Re: Rewriting Three Regexes as One by jeffa (Bishop) on May 04, 2002 at 14:55 UTC
How about `m/\S+=\S+/` instead of alteration? `while (<DATA>) { print if /\S+=\S+/; } __DATA__ $foo = 'hello'; $bar= 'hello'; $baz ='hello'; $qux='hello';` [download] UPDATE: Hope i am not second guessing myself, but i believe i am wrong here. You want only the bar, baz, and qux lines - correct? Looks like your answer is the right way. Sorry, that's what i get for posting before morning coffee. ;) jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l] [select]
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Re: Rewriting Three Regexes as One by arunhorne (Pilgrim) on May 04, 2002 at 11:27 UTC
OK, I found the answer myself. Just in case anyone else ever has the same problem... its because I included brackets!! The following will work fine. I felt they improved readability, but this is no good at the expense of it not working ;D `m/\S=\S\| =\S\|\S= /g` Sorry people.	[reply] [d/l]
Re: Re: Rewriting Three Regexes as One by Sidhekin (Priest) on May 05, 2002 at 02:58 UTC
`m/\S=\S\| =\S\|\S= /g` [download] Since you are concerned about readability, here is what I would prefer ... not that everyone thinks like me, but at least you have one more option :-) `# Bad: m/[\S ]=[\S ]/g m/(?!: = ).=./gs` [download] Update:I should not post this early ... I misread the specs. Without doing capturing braces (and you don't want that, I gather), I can do no better than your version. Update 2:Added the negative lookahead version. The Sidhekin `print "Just another Perl ${\(trickster and hacker)},"`	[reply] [d/l] [select]