删除字符串开头和结尾的空格

Question

我在删除字符串开头和结尾的空格时遇到了问题。例如我有一个像这样的字符串：

\r\n\t- Someone will come here?\n- I don't know for sure...\r\n\r\n

而且我需要删除结尾和开头的空格仅（字符串应该如下所示： - Someone will come here?\n- I don't know for sure... 也可能有很多字符串结尾的变体：“\r\n\r\n”、“\r\n”、“\n\r\n”等等...

谢谢。

Answer 1

您可以先从开头删除，然后从结尾删除，如下所示：

while true {
if sentence.characters.first == "\r\n" || sentence.characters.first == "\n" {
    sentence.removeAtIndex(sentence.startIndex)
} else {
    break
}
}

while true {
if sentence.characters.last == "\r\n" || sentence.characters.last == "\n" {
    sentence.removeAtIndex(sentence.endIndex.predecessor())
} else {
    break
}
}

Answer 2

您的字符串不仅包含空格，还包含换行符。

将 stringByTrimmingCharactersInSet 与 whitespaceAndNewlineCharacterSet 结合使用。

let string = "\r\n\t- Someone will come here?\n- I don't know for sure...\r\n\r\n"
let trimmedString = string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())

在 Swift 3 中清理得更多:

let trimmedString = string.trimmingCharacters(in: .whitespacesAndNewlines)

Answer 3

您可以使用此扩展程序，只需调用 "yourString".trim()

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

Answer 4

//here i have used regular expression and replaced white spaces at the start and end
      let stringPassing : NSString? = "hdfjkhsdj hfjksdhf sdf "
      do {
        print("old->\(stringPassing)")
        let pattern : String = "(^\s+)|(\s+)$"
        let regex = try NSRegularExpression(pattern: pattern , options: [])
        let newMatched = regex.matchesInString(stringPassing! as String, options: [], range: NSMakeRange(0,stringPassing!.length))
        if(newMatched.count > 0){

          let modifiedString = regex.stringByReplacingMatchesInString(stringPassing! as String, options: [] , range: NSMakeRange(0,stringPassing!.length), withTemplate: "")
              print("new->\(modifiedString)")
        }

    } catch let error as NSError {
        print(error.localizedDescription)
    }

Answer 5

字符串修剪第一个和最后一个白色spaces 和 Swift 中的换行符 4+

"  2 space  ".trimmingCharacters(in: .whitespacesAndNewlines)

结果： “2 space”

Answer 6

let string = " example "

let trimmed = string.replacingOccurrences(of: "(^\s+)|(\s+)$", with: "", options: .regularExpression)

print(">" + trimmed3 + "<")

// 打印 >示例<

Answer 7

在此代码中限制文本字段以白色开头space

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        if (textField.text?.count)! == 0 && string == " " {
            return false
        }
        else{
            return true
        }
    }

Answer 8

在Swift4 在任何 String 类型变量上使用它。

extension String {
    func trimWhiteSpaces() -> String {
        let whiteSpaceSet = NSCharacterSet.whitespaces
        return self.trimmingCharacters(in: whiteSpaceSet)
    }
}

并这样称呼它

yourString.trimWhiteSpaces()

Answer 9

如果你想从字符串的开头删除空格试试这个代码。

func removeSpace()->String{
    let txt = myString
    var count:Int! = 0
    for i in txt{
        if i  == " "{
            count += 1
        }else{
            if count != 0{
                return String(txt.dropFirst(count))
            }else{
                return txt
            }
        }
    }
    return ""
}

`

Answer 10

删除字符串开头的所有空格

func removeWhiteSpaces(str:String) -> String{
    var newStr = str
    for i in 0..<str.count{
        let index = str.index(str.startIndex, offsetBy: i)
        print(str[index])
        if str[index] != " "{
            return newStr
        }
        else{
            newStr.remove(at: newStr.startIndex)
        }
    }
    return newStr
}

删除字符串开头和结尾的空格

removing white spaces at beginning and end of string

string

whitespace

trim

ios

swift