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RegEx Pattern Issue

Posted on 2014-07-23
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Last Modified: 2014-10-23
The issue I have is that I am trying to replace words in a text string which is fairly straight forward except for one small twist the .S .T P. in the names.  The are words that I am replace in the text strings that match part but not all of the name.  For example.  FLBOX58 and FLBOX58.T are both valid.  Obviously I only want FLBOX58 to match when the .T is not on the end.  How can I make sure the word patterns match exactly?

P.BASEPRICE.S DLINE.T FLBOX58.T
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Question by:WH_Tech
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käµfm³d   👽 earned 500 total points
ID: 40215858
You would use a negative lookahead for this:

Regex reg = new Regex("FLBOX58(?!\.S|\.T|\.P)");

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The lookahead part is:

(?!\.S|\.T|\.P)

The ! means it's negative. What the lookahead does is that once the "main" pattern matches, the lookahead peeks forward to compare what follows. Since the lookahead is negative, we are saying that the items listed within the lookahead should not be matched. In other words, once we match "FLBOX58", we ensure that we do not find a .S, .T, or a .P. If one is found, then we don't have an overall match.
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Expert Comment

by:Terry Woods
ID: 40215910
No points please.

Tidying up kaufmed's pattern, if you prefer it this way:
Regex reg = new Regex("FLBOX58(?!\.[STP])");

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