类型'String.Index'不符合协议'IntegerLiteralConvertible'

问题描述

使用Beta 3一切正常，现在我得到一个奇怪的错误，我不知道如何解决它。尝试了类似问题的所有解决方案。

With Beta 3 all worked fine, now I get a strange error, and I have no clue how to fix it. Tried all the solutions for similiar problems.

这是我的代码：

if !name.isEmpty {
        var splitted: [String] = name.componentsSeparatedByString(" ")

        for curPart in splitted {
            if !curPart.isEmpty {
                acronym += curPart.substringToIndex(1) //Error
            }
        }
        if (acronym as NSString).length > 2 {
            acronym = acronym.substringToIndex(2) //Error
        }
    }

两条标记的行都给出了同样的错误：

Both marked lines gave me the same error:

有人能帮帮我吗？或者Beta 4被窃听？
谢谢！

Can someone help me? Or is Beta 4 bugged?Thanks!

推荐答案

在测试版4中，Swift的String.Index处理再次改变了 - 你现在不能当需要 String.Index 时，提供 Int 。处理它的方法是创建 String.Index ，你需要使用 advance 方法：

In beta 4, Swift's String.Index handling changed yet again -- you now can't supply an Int when a String.Index is expected. The way to handle it is by creating the String.Index you need using the advance method:

if !name.isEmpty {
    var splitted: [String] = name.componentsSeparatedByString(" ")

    for curPart in splitted {
        if !curPart.isEmpty {
            acronym += curPart.substringToIndex(advance(curPart.startIndex, 1))
        }
    }
    if countElements(acronym) > 2 {
        acronym = acronym.substringToIndex(advance(acronym.startIndex, 2))
    }
}

这都是基于确保正确处理Unicode字符串 - 因为不同的Unicode字符可以有不同的大小，纯整数索引会隐藏字符串不是随机访问的事实。

This is all based on making sure Unicode strings are handled properly - since different Unicode characters can have different sizes, pure integer indexing would hide the fact that Strings aren't random access.

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