Convert unicode scalar emoji to String in Swift

问题

I'm getting unicode scalar for emojis in a text string that I get from a server, which fail to show up as emojis when I print them in a UILabel. This is the format in which I get my string from server:

let string = "Hi, I'm lily U+1F609"

This doesn't work unless it's changed to

let string = "Hi, I'm lily \u{1F609}"

Is there anyway I can convert the string to the required format?

I don't want to use a regex to determine occurrences of U+<HEX_CODE> and then converting them to \u{HEX_CODE}. There has to be a better way of doing this.

回答1:

This is the very kind of problems that regex was created for. If there's a simpler non-regex solution, I'll delete this answer:

func replaceWithEmoji(str: String) -> String {
    var result = str

    let regex = try! NSRegularExpression(pattern: "(U\\+([0-9A-F]+))", options: [.CaseInsensitive])
    let matches = regex.matchesInString(result, options: [], range: NSMakeRange(0, result.characters.count))

    for m in matches.reverse() {
        let range1 = m.rangeAtIndex(1)
        let range2 = m.rangeAtIndex(2)

        if let codePoint = Int(result[range2], radix: 16) {
            let emoji = String(UnicodeScalar(codePoint))
            let startIndex = result.startIndex.advancedBy(range1.location)
            let endIndex = startIndex.advancedBy(range1.length)

            result.replaceRange(startIndex..<endIndex, with: emoji)
        }
    }

    return result
}

来源：https://stackoverflow.com/questions/37938823/convert-unicode-scalar-emoji-to-string-in-swift