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Re: Regular Expressions
Wayne Landsman wrote:
> The following is probably a simple question for anyone familiar with
> regular expressions, but I am still trying to learn the STREGEX
> Suppose I want to find the first occurence in a string of an 'l' ithat
> is not part of a double 'l'. For
> example, in the string
> IDL> st = 'The rolling hills and lake'
> I want to return the character position of the 'l' in lake (=21).
> The following expression almost works -- it will search for any 'l'
> which is both preceded and followed by anything that is not "l"
> IDL> print,stregex(st, '[^l]l[^l]' )
> but it won't work for the string 'The rolling hills and pool' because
> the final 'l' has no characters following it. Any suggestions?
IDL> print, stregex(st,'(^|[^l])l($|[^l])')
which means "a character that is not 'l', or the beginning of the
string, followed by an 'l', followed by a character that is not 'l', or
the end of the string". Aren't you glad Ken Thompson didn't decide
originally to develop regexps in english?
This will also work on
IDL> st = "let's all go the the movies"