Is it possible to write a Swift function that replaces only part of an extended grapheme cluster like 👩‍👩‍👧‍👧?

Question

I want to write a function that could be used like this:

let 👩‍👩‍👧‍👦 = "👩‍👩‍👧‍👧".replacingFirstOccurrence(of: "👧", with: "👦")

Given how odd both this string and Swift's String library are, is this possible in Swift?

Answer 1

Using the range(of:options:range:locale:) the solution became quite concise:

extension String {
    func replaceFirstOccurrence(of searchString: String, with replacementString: String) -> String {
        guard let range = self.range(of: searchString, options: .literal) else { return self }
        return self.replacingCharacters(in: range, with: replacementString)
    }
}

This works by first finding the range of searchString within the instance, and if a range is found the range is replaced with replacementString. Otherwise the instance just returns itself. And, since the range(of:) method returns as soon as it finds a match, the returned range is guaranteed to be the first occurrence.

"221".replaceFirstOccurrence(of: "2", with: "3")                // 321
"👩‍👩‍👧‍👦".replaceFirstOccurrence(of: "\u{1f469}", with: "\u{1f468}") // 👨‍👩‍👧‍👦

^{*To clarify, the last test case converts woman-woman-girl-boy to man-woman-girl-boy.}