Question

I’am trying to filter a string using Regex, I want to filter the PÑ combination out of my string, and also some Seperate P‘s, However in the string that gets provided are also some parts of text like: PB00121324, I want to keep that P.

this is the string:

PB014EC8F;1359300102;NL1200000001 ;Ey³ PÑ PÑ B014EC8F;1359 P B014EC8F;1359

I want to filter out: seperate P‘s and PÑ‘s

So that the output would be this:

PB014EC8F;1359300102;NL1200000001 ;Ey³

I’am now using this code:

string CleanString = Regex.Replace(DirtyString, @"[\\PÑ?]", "");

The problem is that it will result this:

B014EC8F;1359300102;NL1200000001 ;Ey³

instead of this:

PB014EC8F;1359300102;NL1200000001 ;Ey³

Does anybody know the Regex for this?

Thanks in advance!

Answer 1

You can use \b to find a word boundary so for example the regex \bP\b will find a P in isolation.

With \bP\b…

Input Hello P Goodbye -> P Matches as it is adjacent to spaces (non-word characters)

Input HelloP Goodbye -> P does not match as it is adjacent to the previous word

Input Hello.P.Hello -> P matches as it is adjacent to non-word characters

Input P Hello -> P matches as it is adjacent to the start of the string and a space.

In response to your comment below – If the first regex [..] is intended to find two full-stops/periods then this is not what it will do. [] denotes a character class and providing duplicate characters in a character class is meaningless. To match two full-stops use \.\.

I’m not sure if combining into one regex is possible as the order of execution is very important…

Hello..P..S is a P in isolation. However after removal of .. we have HelloPS which is not a P in isolation. To combine multiple replace is easy but they will all effectively happen ‘at the same time’ whereas your current method is doing one, then the next, then the next. ie – The input is different on each occasion.

However to combine the replaces you would do…

 string cleanData = 
 Regex.Replace(DisplayText, @"(\.\.|\bPÑ?\b| )", ""); //untested :)

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