How can I replace a match only at a certain position inside the string?

Question

So, I have a function which has two params: string and match index to replace and i need to replace only match with that index. How can i do that?

Example:

Answer 1

Javascript match returns an array, in case of multiple matches, so you could so something like this:

var string = "....";
var patt1 = /..../gi;
var results = string.match(patt1);
var newString = results.splice(i, i).join();

Instead of using a match, you could use split instead in your specific case:

var results = string.split("_");
var newString = results.splice(i, i).join("_");

It depends on how your input data can vary and where you need to do the split/match (that is why I did not specify any regex above, the split example is complete)...