作为WMios答案的替代方案，您还可以使用componentsSeparatedByCharactersSet，这在分隔符（空格、逗号等）较多的情况下非常方便。

使用您的特定输入：

let separators = NSCharacterSet(charactersInString: " ")
var fullName: String = "First Last";
var words = fullName.componentsSeparatedByCharactersInSet(separators)

// words contains ["First", "Last"]

使用多个分隔符：

let separators = NSCharacterSet(charactersInString: " ,")
var fullName: String = "Last, First Middle";
var words = fullName.componentsSeparatedByCharactersInSet(separators)

// words contains ["Last", "First", "Middle"]

Swift Dev.4.0（2017年5月24日）

Swift 4（Beta版）中拆分了一个新功能。

import Foundation
let sayHello = "Hello Swift 4 2017";
let result = sayHello.split(separator: " ")
print(result)

输出：

["Hello", "Swift", "4", "2017"]

访问值：

print(result[0]) // Hello
print(result[1]) // Swift
print(result[2]) // 4
print(result[3]) // 2017

Xcode 8.1/Swift 3.0.1

这是多个分隔符与数组的方式。

import Foundation
let mathString: String = "12-37*2/5"
let numbers = mathString.components(separatedBy: ["-", "*", "/"])
print(numbers)

输出：

["12", "37", "2", "5"]

只需在fullName上调用componentsSeparatedByString方法

import Foundation

var fullName: String = "First Last"
let fullNameArr = fullName.componentsSeparatedByString(" ")

var firstName: String = fullNameArr[0]
var lastName: String = fullNameArr[1]

Swift 3更新+

import Foundation

let fullName    = "First Last"
let fullNameArr = fullName.components(separatedBy: " ")

let name    = fullNameArr[0]
let surname = fullNameArr[1]

大多数这些答案都假设输入包含一个空格，而不是空白，并且只有一个空格。如果你能安全地做出这样的假设，那么（来自bennett的）公认的答案是相当优雅的，也是我在可能的时候会采用的方法。

当我们无法做出这一假设时，一个更稳健的解决方案需要涵盖以下大多数答案没有考虑的情况：

制表符/换行符/空格（空白），包括重复出现的字符前导/尾随空格Apple/Linux（\n）和Windows（\r\n）换行符

为了涵盖这些情况，此解决方案使用正则表达式将所有空格（包括重复出现的字符和Windows换行符）转换为单个空格，然后修剪，然后拆分为单个空格：

斯威夫特3:

let searchInput = "  First \r\n \n \t\t\tMiddle    Last "
let searchTerms = searchInput 
    .replacingOccurrences(
        of: "\\s+",
        with: " ",
        options: .regularExpression
    )
    .trimmingCharacters(in: .whitespaces)
    .components(separatedBy: " ")

// searchTerms == ["First", "Middle", "Last"]

这里是我刚刚构建的一个算法，它将通过数组中的任何字符分割字符串，如果有任何希望保留具有分割字符的子字符串，可以将swall参数设置为true。

Xcode 7.3-Swift 2.2：

extension String {

    func splitBy(characters: [Character], swallow: Bool = false) -> [String] {

        var substring = ""
        var array = [String]()
        var index = 0

        for character in self.characters {

            if let lastCharacter = substring.characters.last {

                // swallow same characters
                if lastCharacter == character {

                    substring.append(character)

                } else {

                    var shouldSplit = false

                    // check if we need to split already
                    for splitCharacter in characters {
                        // slit if the last character is from split characters or the current one
                        if character == splitCharacter || lastCharacter == splitCharacter {

                            shouldSplit = true
                            break
                        }
                    }

                    if shouldSplit {

                        array.append(substring)
                        substring = String(character)

                    } else /* swallow characters that do not equal any of the split characters */ {

                        substring.append(character)
                    }
                }
            } else /* should be the first iteration */ {

                substring.append(character)
            }

            index += 1

            // add last substring to the array
            if index == self.characters.count {

                array.append(substring)
            }
        }

        return array.filter {

            if swallow {

                return true

            } else {

                for splitCharacter in characters {

                    if $0.characters.contains(splitCharacter) {

                        return false
                    }
                }
                return true
            }
        }
    }
}

例子：

"test text".splitBy([" "]) // ["test", "text"]
"test++text--".splitBy(["+", "-"], swallow: true) // ["test", "++" "text", "--"]

最简单的方法是使用组件SeparatedBy:

对于Swift 2：

import Foundation
let fullName : String = "First Last";
let fullNameArr : [String] = fullName.componentsSeparatedByString(" ")

// And then to access the individual words:

var firstName : String = fullNameArr[0]
var lastName : String = fullNameArr[1]

对于Swift 3：

import Foundation

let fullName : String = "First Last"
let fullNameArr : [String] = fullName.components(separatedBy: " ")

// And then to access the individual words:

var firstName : String = fullNameArr[0]
var lastName : String = fullNameArr[1]