class SpaceRemover
{
    func SpaceRemover(str :String)->String
    {
        var array = Array(str)
        var i = array.count
        while(array.last == " ")
        {
            var array1 = [Character]()
            for item in  0...i - 1
            {
                array1.append(array[item])
            }
            i = i - 1
            array = array1
            print(array1)
            print(array)

        }

        var arraySecond = array
        var j = arraySecond.count

        while(arraySecond.first == " ")
        {
            var array2 = [Character]()
            if j > 1
            {
                for item in 1..<j
                {
                    array2.append(arraySecond[item])
                }
            }
            j = j - 1
            arraySecond = array2
            print(array2)
            print(arraySecond)

        }
        print(arraySecond)
        return String(arraySecond)
    }
}

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

当你想要删除所有类型的空白时(基于这个SO答案)的正确方法是:

extension String {
    var stringByRemovingWhitespaces: String {
        let components = componentsSeparatedByCharactersInSet(.whitespaceCharacterSet())
        return components.joinWithSeparator("")
    }
}

Swift 3.0+ (3.0, 3.1, 3.2, 4.0)

extension String {
    func removingWhitespaces() -> String {
        return components(separatedBy: .whitespaces).joined()
    }
}

EDIT

这个答案是在问题是关于删除所有空白时发布的，问题被编辑为只提到前导空白。如果你只想删除前导空白，请使用以下方法:

extension String {
    func removingLeadingSpaces() -> String {
        guard let index = firstIndex(where: { !CharacterSet(charactersIn: String($0)).isSubset(of: .whitespaces) }) else {
            return self
        }
        return String(self[index...])
    }
}

在Swift 4修剪空白

let strFirstName = txtFirstName.text?.trimmingCharacters(in: 
 CharacterSet.whitespaces)

如果有人从字符串中删除额外的空格，例如= "这是演示文本，请在单词之间删除额外的空格。"

你可以在Swift 4中使用这个函数。

func removeSpace(_ string: String) -> String{
    var str: String = String(string[string.startIndex])
    for (index,value) in string.enumerated(){
        if index > 0{
            let indexBefore = string.index(before: String.Index.init(encodedOffset: index))
            if value == " " && string[indexBefore] == " "{
            }else{
                str.append(value)
            }
        }
    }
    return str
}

结果是

"This is the demo text remove extra space between the words."

你也可以使用正则表达式。

let trimmedString = myString.stringByReplacingOccurrencesOfString("\\s", withString: "", options: NSStringCompareOptions.RegularExpressionSearch, range: nil)