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Old 04-29-2005, 03:12 PM   #1
scuffell
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Regexp question


Hi,

I am using a regular expression in perl.

What I want to do is swap every occurence of + for - and every occurence of - for +.

For example:

I want to change:

2-4+1+6-3

to...

2+4-1-6+3.

Unfortunately, I'm not sure you can do this with 2 regexps, because:

2-4+1+6-3
(change all +s to -s)
2-4-1-6-3
(change all -s to +s)
2+4+1+6+3


Any ideas?

Thanks
 
Old 04-29-2005, 03:50 PM   #2
acid_kewpie
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use an intermediate character... change + for =, - for + and = for -
 
Old 04-29-2005, 03:55 PM   #3
scuffell
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Thanks a lot!
 
Old 04-29-2005, 03:58 PM   #4
rjlee
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Use a translation regexp, not a substitution one:
Code:
my $x='1+2-3+4';
$x =~ tr/+-/-+/;
print "$x\n"
This produces:
Code:
1-2+3-4
 
Old 04-30-2005, 03:35 AM   #5
acid_kewpie
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hmm. yeah that would make more sense huh....
 
  


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