Replace/Remove characters that do not match the Regular Expression (.NET)

c# regex replace remove-if
tif picture tif · May 27, 2011 · Viewed 35.4k times · Source

I have a regular expression to validate a string. But now I want to remove all the characters that do not match my regular expression.

E.g.

regExpression = @"^([\w\'\-\+])"

text = "This is a sample text with some invalid characters -+%&()=?";

//Remove characters that do not match regExp.

result = "This is a sample text with some invalid characters -+";

Any ideas of how I can use the RegExpression to determine the valid characters and remove all the other ones.

Many thanks

Answer

emfurry picture emfurry · May 27, 2011

I believe you can do this (whitelist characters and replace everything else) in one line:

var result = Regex.Replace(text, @"[^\w\s\-\+]", "");

Technically it will produce this: "This is a sample text with some invalid characters - +" which is slightly different than your example (the extra space between the - and +).

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