正则表达式替换

Question

If I have an string like this:

MyObject[0]

I want to use a RegEx to insert a () before the `[

So I would end up with:

MyObject()[0]

I used String.Replace but that could end up causing problems if there's already a () .

.Replace("[", "()[")

Example:

MyObject()[0].Items[0]

Would end up

MyObject()()[0].Items()[0]

Wanting to use a regex to do this to avoid duplication.

Regex.Replace(s, @"[A-Za-z]\[", "()[");

The problem here is it replaces the preceding character:

MyObjec()[0]

Suggestions?

Answer 1

use a grouping around the AZ block in your replace to bring back your t :

Regex.Replace(s, @"([A-Za-z])\[", "$1()[");

Test from LinqPad:

Regex.Replace("MyObject[0]", @"([A-Za-z])\[", "$1()[")

Output:

MyObject()[0]

Answer 2

Just look for word characters followed by [ and only replace in that case (vs. if the word characters are followed by (.

For example:

 Regex.Replace(
  input, 
  //find expression
  @"(\w+)(\[)", 
  //replacement expression
  @"$1()$2")