Swift 2.0:"enumerate"不可用:在序列上调用"enumerate()"方法

问题描述

只需下载Xcode 7 Beta，该错误就会出现在enumerate关键字上.

Just downloaded Xcode 7 Beta, and this error appeared on enumerate keyword.

for (index, string) in enumerate(mySwiftStringArray)
{

}

有人可以帮助我克服这个问题吗?

Can anyone help me overcome this ?

此外，似乎count()不再可以用于计算String的长​​度.

Also, seems like count() is no longer working for counting length of String.

let stringLength = count(myString)

在上面一行，编译器说:

On above line, compiler says :

Apple是否发布了任何有关Swift 2.0的编程指南?

Has Apple has released any programming guide for Swift 2.0 ?

推荐答案

许多全局函数已被协议扩展方法取代，Swift 2的新功能，因此enumerate()现在是扩展方法对于SequenceType:

Many global functions have been replaced by protocol extension methods,a new feature of Swift 2, so enumerate() is now an extension methodfor SequenceType:

extension SequenceType {
    func enumerate() -> EnumerateSequence<Self>
}

并用作

let mySwiftStringArray = [ "foo", "bar" ]
for (index, string) in mySwiftStringArray.enumerate() {
   print(string)
}

并且String不再符合SequenceType，您必须使用characters属性获取Unicode的集合人物.另外，count()是的协议扩展方法CollectionType而不是全局函数:

And String does no longer conform to SequenceType, you have touse the characters property to get the collection of Unicodecharacters. Also, count() is a protocol extension method ofCollectionType instead of a global function:

let myString = "foo"
let stringLength = myString.characters.count
print(stringLength)

Swift 3的更新:enumerate()已重命名为enumerated():

let mySwiftStringArray = [ "foo", "bar" ]
for (index, string) in mySwiftStringArray.enumerated() {
    print(string)
}

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