这个String扩展删除了字符串中的所有空格，而不仅仅是尾随空格…

 extension String {
    func replace(string:String, replacement:String) -> String {
        return self.replacingOccurrences(of: string, with: replacement, options: NSString.CompareOptions.literal, range: nil)
    }

    func removeWhitespace() -> String {
        return self.replace(string: " ", replacement: "")
    }
  }

例子:

let string = "The quick brown dog jumps over the foxy lady."
let result = string.removeWhitespace() // Thequickbrowndogjumpsoverthefoxylady.

如果你想要从前面(和后面)而不是中间删除空格，你应该使用stringByTrimmingCharactersInSet

    let dirtyString   = " First Word "
    let cleanString = dirtyString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())

如果你想从字符串的任何地方删除空格，那么你可能需要查看stringbyreplacement…

删除字符串中的所有空格:

let space_removed_string = (yourstring?.components(separatedBy: " ").joined(separator: ""))!

你也可以试试这个

   let updatedString = searchedText?.stringByReplacingOccurrencesOfString(" ", withString: "-")

对于swift 3.0

import Foundation

var str = " Hear me calling"

extension String {
    var stringByRemovingWhitespaces: String {
        return components(separatedBy: .whitespaces).joined()
    }
}

str.stringByRemovingWhitespaces  // Hearmecalling

Swift 3版本

  //This function trim only white space:
   func trim() -> String
        {
            return self.trimmingCharacters(in: CharacterSet.whitespaces)
        }
    //This function trim whitespeaces and new line that you enter:
     func trimWhiteSpaceAndNewLine() -> String
        {
            return self.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        }