CODEWITHSUNDEEP
c#.netregex
Josh Kodroff
Josh Kodroff

Reputation: 28101

How do you do case-insensitive string replacement using regular expressions?

I know precisely zilch about regular expressions and figured this was as good an opportunity as any to learn at least the most basic of basics.

How do I do this case-insensitive string replacement in C# using a regular expression?

myString.Replace("/kg", "").Replace("/KG", "");

(Note that the '/' is a literal.)

Upvotes: 35

Views: 36635

Answers (6)

Jon Skeet
Jon Skeet

Reputation: 1499780

You can use:

myString = Regex.Replace(myString, "/kg", "", RegexOptions.IgnoreCase);

If you're going to do this a lot of times, you could do:

// You can reuse this object
Regex regex = new Regex("/kg", RegexOptions.IgnoreCase);
myString = regex.Replace(myString, "");

Using (?i:/kg) would make just that bit of a larger regular expression case insensitive - personally I prefer to use RegexOptions to make an option affect the whole pattern.

MSDN has pretty reasonable documentation of .NET regular expressions.

Upvotes: 83

Guffa
Guffa

Reputation: 700182

Like this:

myString = Regex.Replace(myString, "/[Kk][Gg]", String.Empty);

Note that it will also handle the combinations /kG and /Kg, so it does more than your string replacement example.

If you only want to handle the specific combinations /kg and /KG:

myString = Regex.Replace(myString, "/(?:kg|KG)", String.Empty);

Upvotes: 6

Brad
Brad

Reputation: 639

Here is an example using the Regex.replace function.

Upvotes: 0

Tim Hoolihan
Tim Hoolihan

Reputation: 12396

    Regex regex = new Regex(@"/kg", RegexOptions.IgnoreCase );
    regex.Replace(input, "");

Upvotes: 0

tom.dietrich
tom.dietrich

Reputation: 8347

"/[kK][gG]" or "(?i:/kg)" will match for you.

declare a new regex object, passing in one of those as your contents. Then run regex.replace.

Upvotes: 2

Philippe Leybaert
Philippe Leybaert

Reputation: 171734

It depends what you want to achieve. I assume you want to remove a sequence of characters after a slash?

string replaced = Regex.Replace(input,"/[a-zA-Z]+","");

or

string replaced = Regex.Replace(input,"/[a-z]+","",RegexOptions.IgnoreCase);

Upvotes: 0

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