不要忘记导入Foundation或UIKit。

import Foundation
let trimmedString = "   aaa  "".trimmingCharacters(in: .whitespaces)
print(trimmedString)

结果:

"aaa"

否则你会得到:

error: value of type 'String' has no member 'trimmingCharacters'
    return self.trimmingCharacters(in: .whitespaces)

在Swift 3.0中

extension String
{   
    func trim() -> String
   {
    return self.trimmingCharacters(in: CharacterSet.whitespaces)
   }
}

你可以打电话

let result = " Hello World ".trim()  /* result = "Hello World" */

extension String {
    /// EZSE: Trims white space and new line characters
    public mutating func trim() {
         self = self.trimmed()
    }

    /// EZSE: Trims white space and new line characters, returns a new string
    public func trimmed() -> String {
        return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
    }
}

从我的这个回购:https://github.com/goktugyil/EZSwiftExtensions/commit/609fce34a41f98733f97dfd7b4c23b5d16416206

不要忘记导入Foundation或UIKit。

import Foundation
let trimmedString = "   aaa  "".trimmingCharacters(in: .whitespaces)
print(trimmedString)

结果:

"aaa"

否则你会得到:

error: value of type 'String' has no member 'trimmingCharacters'
    return self.trimmingCharacters(in: .whitespaces)

在Swift3 XCode 8 Final中

注意CharacterSet。空格不再是函数了!

(NSCharacterSet.whitespaces也不是)

extension String {
    func trim() -> String {
        return self.trimmingCharacters(in: CharacterSet.whitespaces)
    }
}

我创建了这个函数，允许输入字符串并返回由任意字符修剪的字符串列表

 func Trim(input:String, character:Character)-> [String]
{
    var collection:[String] = [String]()
    var index  = 0
    var copy = input
    let iterable = input
    var trim = input.startIndex.advancedBy(index)

    for i in iterable.characters

    {
        if (i == character)
        {

            trim = input.startIndex.advancedBy(index)
            // apennding to the list
            collection.append(copy.substringToIndex(trim))

            //cut the input
            index += 1
            trim = input.startIndex.advancedBy(index)
            copy = copy.substringFromIndex(trim)

            index = 0
        }
        else
        {
            index += 1
        }
    }
    collection.append(copy)
    return collection

}

As在swift中没有找到这样做的方法(在swift 2.0中编译和工作完美)