Swift 5 isEmoji 方法 returns 对数字正确吗？

Question

就像下面的例子 isEmoji 方法 returns true 对于 number :

let scalars: [Unicode.Scalar] = ["", "+", "1"]
for s in scalars {
    print(s, "-->", s.properties.isEmoji)
}
//  --> true
// + --> false
// 1 --> true... wait what?

但是 为什么 和如何确定我示例中的最后一个案例。

Answer 1

遇到这个问题后我稍微搜索了一下，在Apple's documentation中找到了答案。我分享给你，以免你以后浪费宝贵的时间：

The final result is true because the ASCII digits have non-default emoji presentations; some platforms render these with an alternate appearance.

Because of this behavior, testing isEmoji alone on a single scalar is insufficient to determine if a unit of text is rendered as an emoji; a correct test requires inspecting multiple scalars in a Character. In addition to checking whether the base scalar has isEmoji == true, you must also check its default presentation (see isEmojiPresentation) and determine whether it is followed by a variation selector that would modify the presentation. This property corresponds to the “Emoji” property in the Unicode Standard.

解决方案

所以你可以像下面这样检查：

let scalars: [Unicode.Scalar] = ["", "+", "1"]
for s in scalars {
    print(s, "-->", (s.properties.isEmoji && s.properties.isEmojiPresentation))
}
//  --> true
// + --> false
// 1 --> false

Swift 5 isEmoji 方法 returns 对数字正确吗？

Swift 5 isEmoji method returns true for a number?

string

emoji

swift

解决方案