VB.Net, regular expression question

regular expression question

Author	Message
Bob #1 / 5	regular expression question I want to replace all occurances of "\cf1 " (where "1" could be any integer) with " " where the expression is not immediately preceded by another "\". Something akin to this: mytext = New Regex("[^\\]\\cf[0-9]+ ").Replace(mytext, " ") Only, I don't want to replace the beginning character [^\\].. I just want to use it as a matching criteria. How do I do that? I'm hoping to be able to accomplish this without loops. Also, why doesn't replacing [0-9]+ in the matching pattern with [:z] work? According to the docs, "cf[0-9]+" and "cf[:z]" should be equivalant but I can't seem to get [:z] to work at all. TIA, Bob
Wed, 12 Oct 2005 02:08:13 GMT

Mike LeBlan #2 / 5	regular expression question Ok, If I understand you correctly you just want: "\cf1 " = " " "\\cf1 " = "\\cf1 " You could do that with: regex.replace(input, (?<!\\)\\cf\d+ ", " ") (?<! <pattern>) tells the RE to not match if the expression begins with <pattern>. Look up regular expressions, character classes in MSDN for more grouping constructs. The [:z] character class is not supported in .NET languages, just in the Visual Studio Find (using regular expressions). Don't ask why they didn't use the same syntax for both shrug. .Net supports \d as the equivalent to [0-9]. Quote: >-----Original Message----- >I want to replace all occurances of "\cf1 " (where "1" could be any integer) Quote: >with " " where the expression is not immediately preceded by another "\". >Something akin to this: >mytext = New Regex("[^\\]\\cf[0-9]+ ").Replace (mytext, " ") >Only, I don't want to replace the beginning character [^\\].. I just want to Quote: >use it as a matching criteria. How do I do that? I'm hoping to be able to Quote: >accomplish this without loops. >Also, why doesn't replacing [0-9]+ in the matching pattern with [:z] work? Quote: >According to the docs, "cf[0-9]+" and "cf[:z]" should be equivalant but I >can't seem to get [:z] to work at all. >TIA, >Bob >.
Wed, 12 Oct 2005 02:47:47 GMT

Bob #3 / 5	regular expression question Oh, yeah. More info about why I'm asking this question... I thought I had found a solution, here's what the docs say: Prevent match ~(X) Prevents a match when X appears at this point in the expression. For example, real~(ity) matches the "real" in "realty" and "really," but not the "real" in "reality." Only the example provided doesn't work at all, and neither do any of my own attempts to use ~(). I hope someone can tell me why. Maybe I'm just being braindead today. TIA, Bob Quote: > I want to replace all occurances of "\cf1 " (where "1" could be any integer) > with " " where the expression is not immediately preceded by another "\". > Something akin to this: > mytext = New Regex("[^\\]\\cf[0-9]+ ").Replace(mytext, " ") > Only, I don't want to replace the beginning character [^\\].. I just want to > use it as a matching criteria. How do I do that? I'm hoping to be able to > accomplish this without loops. > Also, why doesn't replacing [0-9]+ in the matching pattern with [:z] work? > According to the docs, "cf[0-9]+" and "cf[:z]" should be equivalant but I > can't seem to get [:z] to work at all. > TIA, > Bob
Wed, 12 Oct 2005 02:48:16 GMT

Bob #4 / 5	regular expression question Thank you, works great. I should have guessed that since that help doc page I was looking at was so easy to use to look up usage, naturally they would find a way to make it useless and instead make me look for answers scattered around multiple pages with titles that don't make any sense to a layman. Silly me! (slaps hand on forehead) Bob Quote: > Ok, > If I understand you correctly you just want: > "\cf1 " = " " > "\\cf1 " = "\\cf1 " > You could do that with: > regex.replace(input, (?<!\\)\\cf\d+ ", " ") > (?<! <pattern>) tells the RE to not match if the > expression begins with <pattern>. Look up > regular expressions, character classes > in MSDN for more grouping constructs. > The [:z] character class is not supported in .NET > languages, just in the Visual Studio Find (using regular > expressions). Don't ask why they didn't use the same > syntax for both shrug. .Net supports \d as the > equivalent to [0-9]. > >-----Original Message----- > >I want to replace all occurances of "\cf1 " (where "1" > could be any integer) > >with " " where the expression is not immediately preceded > by another "\". > >Something akin to this: > >mytext = New Regex("[^\\]\\cf[0-9]+ ").Replace > (mytext, " ") > >Only, I don't want to replace the beginning character > [^\\].. I just want to > >use it as a matching criteria. How do I do that? I'm > hoping to be able to > >accomplish this without loops. > >Also, why doesn't replacing [0-9]+ in the matching > pattern with [:z] work? > >According to the docs, "cf[0-9]+" and "cf[:z]" should be > equivalant but I > >can't seem to get [:z] to work at all. > >TIA, > >Bob > >.
Wed, 12 Oct 2005 03:11:54 GMT

WildNit #5 / 5	regular expression question I have had the same problem with the C# documentation in .NET. It clearly states "real~(ity)" matches "real" in "really" but not in "reality"... and then you discover that the example doesn't work! I built the regular expression "real(?!ity)", this matches the "real" in "really" but does not match the "real" in "really". I'm unsure as to where the documented example came from (and to be honest I'm not sure how the above example works, as the syntax is undescribed), but this works now. Hope that's some help. Chris Fox Quote: > Oh, yeah. More info about why I'm asking this question... I thought I had > found a solution, here's what the docs say: > Prevent match > ~(X) > Prevents a match when X appears at this point in the expression. For > example, real~(ity) matches the "real" in "realty" and "really," but not the > "real" in "reality." > Only the example provided doesn't work at all, and neither do any of my own > attempts to use ~(). > I hope someone can tell me why. Maybe I'm just being braindead today. > TIA, > Bob > > I want to replace all occurances of "\cf1 " (where "1" could be any > integer) > > with " " where the expression is not immediately preceded by another "\". > > Something akin to this: > > mytext = New Regex("[^\\]\\cf[0-9]+ ").Replace(mytext, " ") > > Only, I don't want to replace the beginning character [^\\].. I just want > to > > use it as a matching criteria. How do I do that? I'm hoping to be able to > > accomplish this without loops. > > Also, why doesn't replacing [0-9]+ in the matching pattern with [:z] work? > > According to the docs, "cf[0-9]+" and "cf[:z]" should be equivalant but I > > can't seem to get [:z] to work at all. > > TIA, > > Bob
Tue, 18 Oct 2005 22:05:30 GMT

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