Re: Regex negative word

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Re^2: Regex negative word by radiantmatrix (Parson) on Mar 30, 2006 at 20:22 UTC
There are a few different approaches. Off the top of my head... `# assume $_ holds the value I'm testing # 1: Two tests if ( /^(?!cat)/ && /dog$/ ) {} # if does not start with cat && ends wi +th dog # 2: take advantage of zero-width assertion in (?!cat) if ( /^(?!cat).dog$/ ) {} # if we start with something that is not 'c +at' # then have 0 or more chars before ending w +ith 'dog' # 3: not using regex at all! if ( index($_, 'cat') != 0 && index($_,'dog') == length($_) - 3 ) {} # if we don't find 'cat' at the head of the string, # && find 'dog' at the end.` [download] <-radiant.matrix-> A collection of thoughts and links from the minds of geeks The Code that can be seen is not the true Code* I haven't found a problem yet that can't be solved by a well-placed trebuchet	[reply] [d/l]

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Re^2: Regex negative word
by radiantmatrix (Parson) on Mar 30, 2006 at 20:22 UTC

There are a few different approaches. Off the top of my head...

# assume $_ holds the value I'm testing

# 1: Two tests
if ( /^(?!cat)/ && /dog$/ ) {} # if does not start with cat && ends wi
+th dog

# 2: take advantage of zero-width assertion in (?!cat)
if ( /^(?!cat).*dog$/ ) {} # if we start with something that is not 'c
+at'
                           # then have 0 or more chars before ending w
+ith 'dog'

# 3: not using regex at all!
if ( 
   index($_, 'cat') != 0 
   && index($_,'dog') == length($_) - 3 
) {}  # if we don't find 'cat' at the head of the string, 
      # && find 'dog' at the end.
[download]

<-radiant.matrix->
A collection of thoughts and links from the minds of geeks
The Code that can be seen is not the true Code
I haven't found a problem yet that can't be solved by a well-placed trebuchet

[reply]
[d/l]