下面是如何从String的开头和结尾删除所有空白。

(使用Swift 2.0测试的示例。)

let myString = "  \t\t  Let's trim all the whitespace  \n \t  \n  "
let trimmedString = myString.stringByTrimmingCharactersInSet(
NSCharacterSet.whitespaceAndNewlineCharacterSet()
)
// Returns "Let's trim all the whitespace"

(用Swift 3+测试的示例。)

let myString = "  \t\t  Let's trim all the whitespace  \n \t  \n  "
let trimmedString = myString.trimmingCharacters(in: .whitespacesAndNewlines)
// Returns "Let's trim all the whitespace"

你可以在Swift String扩展https://bit.ly/JString中使用trim()方法。

var string = "hello  "
var trimmed = string.trim()
println(trimmed)// "hello"

把这段代码放在你项目的一个文件中，比如Utils.swift:

extension String
{
func trim() -> String
{
return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
}
}

所以你可以这样做:

let result = " abc ".trim()
// result == "abc"

Swift 3.0解决方案

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

所以你可以这样做:

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

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)

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

将字符串截断为特定长度

如果你已经输入了一段句子/文本，你想只保存指定长度的文本。将以下扩展添加到类中

extension String {


func trunc(_ length: Int) -> String {
if self.characters.count > length {
return self.substring(to: self.characters.index(self.startIndex, offsetBy: length))
} else {
return self
}
}


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


}

使用

var str = "Lorem Ipsum is simply dummy text of the printing and typesetting industry."
//str is length 74
print(str)
//O/P:  Lorem Ipsum is simply dummy text of the printing and typesetting industry.


str = str.trunc(40)
print(str)
//O/P: Lorem Ipsum is simply dummy text of the

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" */

斯威夫特3

let result = " abc ".trimmingCharacters(in: .whitespacesAndNewlines)

是的，你可以这样做:

var str = "  this is the answer   "
str = str.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
print(srt) // "this is the answer"

CharacterSet实际上是一个非常强大的工具，用于创建修剪规则，比. whitespacesandnewlines等预定义集更灵活。

例如:

var str = " Hello World !"
let cs = CharacterSet.init(charactersIn: " !")
str = str.trimmingCharacters(in: cs)
print(str) // "Hello World"

在Swift3 XCode 8 Final中

注意CharacterSet.whitespaces不再是函数了!

(NSCharacterSet.whitespaces也不是)

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

另一种类似的方式:

extension String {
var trimmed:String {
return self.trimmingCharacters(in: CharacterSet.whitespaces)
}
}

使用:

let trimmedString = "myString ".trimmed

Swift 5 &4.2

let trimmedString = " abc ".trimmingCharacters(in: .whitespaces)
//trimmedString == "abc"

别忘了import 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)

//Swift 4.0删除空格和新行

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

您还可以发送您想要修剪的字符

extension String {




func trim() -> String {


return self.trimmingCharacters(in: .whitespacesAndNewlines)


}


func trim(characterSet:CharacterSet) -> String {


return self.trimmingCharacters(in: characterSet)


}
}


validationMessage = validationMessage.trim(characterSet: CharacterSet(charactersIn: ","))

**Swift 5**


extension String {


func trimAllSpace() -> String {
return components(separatedBy: .whitespacesAndNewlines).joined()
}
    

func trimSpace() -> String {
return self.trimmingCharacters(in: .whitespacesAndNewlines)
}
}


**Use:**
let result = " abc ".trimAllSpace()
// result == "abc"
let ex = " abc cd  ".trimSpace()
// ex == "abc cd"