遍历String Swift 2.0 [英] Iterate through a String Swift 2.0

问题描述

我正在尝试在Swift操场上编写一段非常简单的代码.

I am trying to do a very simple piece of code in Swift playgrounds.

var word = "Zebra"

for i in word {
  print(i)
}

但是，我总是在第3行出现错误.

However, I always get an error on line 3.

字符串"没有名为生成器"的成员

'String' does not have a member named 'Generator'

关于这为什么不起作用的任何想法?注意:我正在使用带有Swift 2.0的Xcode 7(字符串和字符).

Any ideas on why this doesn't work? Note: I am working in Xcode 7, with Swift 2.0 (Strings and Characters).

推荐答案

从Swift 2开始，String不符合SequenceType.但是，可以在String上使用characters属性. characters返回

As of Swift 2, String doesn't conform to SequenceType. However, you can use the characters property on String. characters returns a String.CharacterView which conforms to SequenceType and so can be iterated through with a for loop:

let word = "Zebra"

for i in word.characters {
    print(i)
}

或者，您可以在String上添加扩展名以使其符合SequenceType:

Alternatively, you could add an extension to String to make it conform to SequenceType:

extension String: SequenceType {}

// Now you can use String in for loop again.
for i in "Zebra" {
    print(i)
}

尽管如此，但我确定Apple有理由删除String与SequenceType的一致性，因此第一种选择似乎是更好的选择.探索有趣的事情是很有趣的.

Although, I'm sure Apple had a reason for removing String's conformance to SequenceType and so the first option seems like the better choice. It's interesting to explore what's possible though.

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