如何知道两个表情符号是否会显示为一个表情符号？

Question

表情符号由 2 个 unicodeScalars U+1F44D、U+1F3FC 组成。

如何将其识别为 1 个 'displayed' 表情符号，因为它将在 iOS 上如此显示？

Answer 1

更新 Swift 4 (Xcode 9)

自 Swift 4 起，"Emoji sequence" 被视为单个字素集群（根据 Unicode 9 标准）：

let s = "ab‍❤️‍‍"
print(s.count) // 4

因此不再需要其他解决方法。

（Swift 3 及更早版本的旧答案:)

一个可能的选择是枚举和计算 "composed character sequences" 中的字符串：

let s = "ab‍❤️‍‍"
var count = 0
s.enumerateSubstringsInRange(s.startIndex..<s.endIndex,
                             options: .ByComposedCharacterSequences) {
                                (char, _, _, _) in
                                if let char = char {
                                    count += 1
                                }
}
print(count) // 4

另一种选择是查找组合字符的范围给定索引处的序列：

let s = "‍❤️‍‍"
if s.rangeOfComposedCharacterSequenceAtIndex(s.startIndex) == s.characters.indices {
    print("This is a single composed character")
}

作为 String 扩展方法：

// Swift 2.2:
extension String {
    var composedCharacterCount: Int {
        var count = 0
        enumerateSubstringsInRange(characters.indices, options: .ByComposedCharacterSequences) {
            (_, _, _, _) in count += 1
        }
        return count
    }

    var isSingleComposedCharacter: Bool {
        return rangeOfComposedCharacterSequenceAtIndex(startIndex) == characters.indices
    }
}

// Swift 3:
extension String {
    var composedCharacterCount: Int {
        var count = 0
        enumerateSubstrings(in: startIndex..<endIndex, options: .byComposedCharacterSequences) {
            (_, _, _, _) in count += 1
        }
        return count
    }

    var isSingleComposedCharacter: Bool {
        return rangeOfComposedCharacterSequence(at: startIndex) == startIndex..<endIndex
    }
}

示例：

"".composedCharacterCount // 1
"".characters.count       // 2

"‍❤️‍‍".composedCharacterCount // 1
"‍❤️‍‍".characters.count       // 4

"".composedCharacterCount // 2
"".characters.count       // 1

如您所见，Swift 个字符（扩展字素簇）的数量可以多于 或少于 组成字符序列的数量。

如何知道两个表情符号是否会显示为一个表情符号？

How to know if two emojis will be displayed as one emoji?

string

unicode

ios

emoji

swift