Is it possible to change text within a specific part of an NSString? For example, I want to use `stringByReplacingOccurrencesOfString`, but only within a certain part of a string. In this example, I only want to replace `#`'s after `#q=`, and before `&lang=en-us`. Like this:

Initial string: `https://google.com/search#q=hello#&lang=en-us`

What it should be replaced with: `https://google.com/search#q=hello%23&lang=en-us`

What using `stringByReplacingOccurrencesOfString` returns if I tell it to replace `#`'s with `%23`: `https://google.com/search%23q=hello%23&lang=en-us`

Thanks for your help!