[英]Does swift have a trim method on String?
swift 在 String 上有修剪方法吗? 例如:
let result = " abc ".trim()
// result == "abc"
这是从String
的开头和结尾删除所有空格的方法。
(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"
(使用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"
将此代码放在项目中的文件中,例如 Utils.swift:
extension String
{
func trim() -> String
{
return self.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
}
}
所以你将能够做到这一点:
let result = " abc ".trim()
// result == "abc"
Swift 3.0 解决方案
extension String
{
func trim() -> String
{
return self.trimmingCharacters(in: NSCharacterSet.whitespaces)
}
}
所以你将能够做到这一点:
let result = " Hello World ".trim()
// result = "HelloWorld"
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" */
let trimmedString = " abc ".trimmingCharacters(in: .whitespaces)
//trimmedString == "abc"
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,可以创建修剪规则,比预定义的集合(如 .whitespacesAndNewlines)具有更大的灵活性。
例如:
var str = " Hello World !"
let cs = CharacterSet.init(charactersIn: " !")
str = str.trimmingCharacters(in: cs)
print(str) // "Hello World"
将字符串截断为特定长度
如果您输入了句子/文本块,并且只想保存指定长度的文本。 将以下扩展添加到类
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)
}
}
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
您可以在我编写的 Swift String 扩展中使用 trim() 方法https://bit.ly/JString 。
var string = "hello "
var trimmed = string.trim()
println(trimmed)// "hello"
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())
}
}
取自我的这个仓库: https : //github.com/goktugyil/EZSwiftExtensions/commit/609fce34a41f98733f97dfd7b4c23b5d16416206
在 Swift3 XCode 8 决赛中
请注意, CharacterSet.whitespaces
不再是一个函数!
(也不是NSCharacterSet.whitespaces
)
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)
}
}
用:
let trimmedString = "myString ".trimmed
//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"
我创建了这个函数,它允许输入一个字符串并返回一个由任何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
}
因为没有找到在 swift 中执行此操作的方法(在 swift 2.0 中编译并完美运行)
不要忘记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)
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