String componentsSeparatedByString 做一次 (String componentsSeparatedByString do one time)

問題描述

String componentsSeparatedByString 做一次 (String componentsSeparatedByString do one time)

我有一個字符串：let mystring = "key=value=value=value=value"

當我這樣做時：

let ar = mystring.componentsSeparatedByString("=")

我得到：

["key", "value", "value", "value", "value"]

但是我只需要拆分一次，例如 componentsSeparatedByString("=", 1)，即可得到：

["key", "value=value=value=value"]

With Swift 2.1, you can use the split function as follows to do what you want:

let result = string.characters.split("=", maxSplit: 1, allowEmptySlices: true)

Some example code to test this would be:

let string = "key=value=value=value=value"
let result = string.characters.split("=", maxSplit: 1, allowEmptySlices: true)
print(String(result[0]))  // "key"
print(String(result[1]))  // "value=value=value=value"

方法 2:

This should do the job

func extract(rawData: String) ‑> [String]? {
    let elms = rawData.characters.split("=", maxSplit: 1).map { String($0) }
    guard let
        key = elms.first,
        value = elms.last
        where elms.count == 2 else { return nil }
    return [key, value]
}

Example:

let rawData = "key=value=value=value=value"
extract(rawData) // > ["key", "value=value=value=value"]

Please note the extract function does an optional array of strings. Infact if the input string does not contain at least an = then nil is returned.

The code has been tested with the Swift 2.1 and Xcode Playground 7.1.1.

Hope this helps.

方法 3:

You're probably going to have to write your own custom code to do that, using either NSScanner or rangeofString:options:range:

EDIT:

Actually, it sounds like the Swift String class's split function, with its maxSplit parameter, will do what you need. Take a look at the link in Preston's answer.

方法 4:

let mystring = "key=value=value=value=value"
let result = split(mystring as String, { $0 == "=" }, maxSplit: 1, allowEmptySlices: true)

result should now be [key, value=value=value=value]

方法 5:

Try this: (tested and working in playground)

var key = str.substringToIndex(str.rangeOfString("=")!.startIndex)
var value = str.substringFromIndex(str.rangeOfString("=")!.startIndex.advancedBy(1))
var resultingArray = [key, value]

(by Arti、keithbhunter、Luca Angeletti、Duncan C、Shabarinath Pabba、Jeremie D)

參考文件

1. String componentsSeparatedByString do one time (CC BY‑SA 2.5/3.0/4.0)