直到Swift 2，我使用这个扩展名来删除多个空格:
func condenseWhitespace() -> String {
let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter({!Swift.isEmpty($0)})
return " ".join(components)
}
但是使用 Swift 2 现在我收到了错误消息
无法调用类型为 '(String)' 的参数列表的 'isEmpty'
如何使用 Swift 2 删除多个空格？ 谢谢！
extension String {
func condenseWhitespace() -> String {
let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
return components.filter { !$0.isEmpty }.joinWithSeparator(" ")
}
}
let result = "Hello World.\nHello!".condenseWhitespace() // "Hello World. Hello!"
extension String {
var condensedWhitespace: String {
let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
return components.filter { !$0.isEmpty }.joinWithSeparator(" ")
}
}
let result = "Hello World.\nHello!".condensedWhitespace // "Hello World. Hello!"
在 Swift 3 中有更多的变化。
函数：
extension String {
func condenseWhitespace() -> String {
let components = self.components(separatedBy: NSCharacterSet.whitespacesAndNewlines)
return components.filter { !$0.isEmpty }.joined(separator: " ")
}
}
let result = "Hello World.\nHello!".condenseWhitespace()
属性：
extension String {
var condensedWhitespace: String {
let components = self.components(separatedBy: NSCharacterSet.whitespacesAndNewlines)
return components.filter { !$0.isEmpty }.joined(separator: " ")
}
}
let result = "Hello World.\nHello!".condensedWhitespace
在Swift 4.2中，NSCharacterSet现在更名为CharacterSet，并且您可以省略并使用点语法：
extension String {
func condenseWhitespace() -> String {
let components = self.components(separatedBy: .whitespacesAndNewlines)
return components.filter { !$0.isEmpty }.joined(separator: " ")
}
}
let result = "Hello World.\nHello!".condenseWhitespace() // "Hello World. Hello!"
将字符串分割成数组，然后再次连接在“非内存有效”的情况下。这需要大量的内存。在这种情况下最好的方法是扫描给定的字符串并对其执行操作。正则表达式是扫描文本的高级方式。给出以下解决方案以得出上述结论：
Swift 4.x
extension String {
func removeExtraSpaces() -> String {
return self.replacingOccurrences(of: "[\\s\n]+", with: " ", options: .regularExpression, range: nil)
}
}
用途
let startingString = "hello world! \n\n I am here!"
let processedString = startingString.removeExtraSpaces()
print(processedString)
输出：
processedString => "你好世界！我在这里！"
根据自己的需求，您可以做更多的事情，但我在这里指出的是要使用字符串正则表达式，而不是创建数组，否则会消耗大量内存。
最清晰的版本。文档齐全，内存占用少，极易使用。
extension String {
/// Returns a condensed string, with no extra whitespaces and no new lines.
var condensed: String {
return replacingOccurrences(of: "[\\s\n]+", with: " ", options: .regularExpression, range: nil)
}
/// Returns a condensed string, with no whitespaces at all and no new lines.
var extraCondensed: String {
return replacingOccurrences(of: "[\\s\n]+", with: "", options: .regularExpression, range: nil)
}
}
let a = " Hello\n I am a string ".condensed
let b = " Hello\n I am a string ".extraCondensed
a: "你好，我是一个字符串"
b: "HelloIamastring"
SWIFT 3：更简洁的版本
extension String {
var condensedWhitespace: String {
let components = self.components(separatedBy: .whitespacesAndNewlines)
return components.filter { !$0.isEmpty }.joined(separator: " ")
}
}
extension String {
func removeExtraSpaces() -> String {
var data = ""
var numberOfSpace = 0
let items = self.getComponents(separatedBy: " ")
for item in items{
if item == " "{
numberOfSpace = numberOfSpace + 1
}else{
numberOfSpace = 0
}
if numberOfSpace == 1 || numberOfSpace == 0 {
data = data + item
//data.append(item)
}
}
return data
}
}
使用方法
var message = "What is the purpose of life?"
message = message.removeExtraSpaces()
print(message)
输出：
生命的目的是什么？
var example = " Hello world "
func removeSpacers(from word: String) -> String {
var finalResult = ""
var spacesCount = 0
let trimmed = word.trimmingCharacters(in: .whitespaces)
let components = trimmed.components(separatedBy: " ")
// if we have not any spaces we returning trimmed string
guard components.contains(where: { $0 == "" }) else { return trimmed }
components.forEach {
// because .components returning ""(empty string)
if $0 == "" {
spacesCount += 1
} else {
// if another element not space, we could add space(the space between words)
if spacesCount != 0 {
spacesCount = 0
finalResult.append(" ")
}
}
// so if we have no spaces we could add word no result string
if spacesCount == 0 {
finalResult.append($0)
}
}
return finalResult
}
我做了几个测试，它们都成功了。 func testRemoveSpaceFromStringWithSpacesOnCenter() {
// given
let string = "Hello world"
// when
let result = pfromatter.removeSpaces(from: string)
// then
let expected = "Hello world"
XCTAssertEqual(expected, result)
}
func testRemoveSpaceFromStringWithSpacesOnSide() {
// given
let string = " Hello world "
// when
let result = pfromatter.removeSpaces(from: string)
// then
let expected = "Hello world"
XCTAssertEqual(expected, result)
}
var str = "Hello World.\nHello!"
if let regex = try? NSRegularExpression(pattern: "\\s+", options:NSRegularExpression.Options.caseInsensitive)
{
str = regex.stringByReplacingMatches(in: str, options: [], range: NSMakeRange(0, str.count), withTemplate: " ")
}
extension String {
func trimmingExtraWhitespace() -> String {
return self.replacingOccurrences(of: "(?<=\\s)\\s+|\\s+(?=$)|(?<=^)\\s+",
with: "",
options: .regularExpression)
}
}
(?<=\\s)\\s+ 匹配所有在空格之前的空白字符\\s+(?=$) 匹配所有在字符串末尾的空白字符(?<=^)\\s+ 匹配所有在字符串开头的空白字符\s 包括空格、制表符和换行符，所以不需要显式指定 \n。\s，因此使用双反斜杠 \\var originalString = " Hello world "
var processedString = originalString.trimmingExtraWhitespace()
print("Original: \(originalString)")
print("Processed: \(processedString)")
输出：
Original: Hello world
Processed: Hello world
func condenseWhitespace() -> String { let components = self.components(separatedBy: .whitespaces) let tmpstr = components.filter { !$0.isEmpty }.joined(separator: " ") let components2 = tmpstr.components(separatedBy: .newlines) return components2.filter { !$0.isEmpty }.joined(separator: "\n") }- Climbatize