在Swift 4.2中

Use

func contains(_ str: String) -> Bool

例子

let string = "hello Swift"
let containsSwift = string.contains("Swift")
print(containsSwift) // prints true

在Xcode 7.1和Swift 2.1中，containsString()为我工作得很好。

let string = "hello swift"
if string.containsString("swift") {
    print("found swift")
}

斯威夫特4:

let string = "hello swift"
if string.contains("swift") {
    print("found swift")
}

一个不区分大小写的Swift 4示例:

let string = "Hello Swift"
if string.lowercased().contains("swift") {
    print("found swift")
}

或者使用不区分大小写的字符串扩展名:

extension String {
    func containsIgnoreCase(_ string: String) -> Bool {
        return self.lowercased().contains(string.lowercased())
    }
}

let string = "Hello Swift"
let stringToFind = "SWIFT"
if string.containsIgnoreCase(stringToFind) {
    print("found: \(stringToFind)")  // found: SWIFT
}
print("string: \(string)")
print("stringToFind: \(stringToFind)")

// console output:
found: SWIFT
string: Hello Swift
stringToFind: SWIFT

这是我在快速操场上的第一次尝试。 我通过提供两个新函数(contains和containsIgnoreCase)来扩展String

extension String {
    func contains(other: String) -> Bool{
        var start = startIndex

        do{
            var subString = self[Range(start: start++, end: endIndex)]
            if subString.hasPrefix(other){
                return true
            }

        }while start != endIndex

        return false
    }

    func containsIgnoreCase(other: String) -> Bool{
        var start = startIndex

        do{
            var subString = self[Range(start: start++, end: endIndex)].lowercaseString
            if subString.hasPrefix(other.lowercaseString){
                return true
            }

        }while start != endIndex

        return false
    }
}

像这样使用它

var sentence = "This is a test sentence"
sentence.contains("this")  //returns false
sentence.contains("This")  //returns true
sentence.containsIgnoreCase("this")  //returns true

"This is another test sentence".contains(" test ")    //returns true

我欢迎任何反馈:)

给你!准备Xcode 8和Swift 3。

import UIKit

let mString = "This is a String that contains something to search."
let stringToSearchUpperCase = "String"
let stringToSearchLowerCase = "string"

mString.contains(stringToSearchUpperCase) //true
mString.contains(stringToSearchLowerCase) //false
mString.lowercased().contains(stringToSearchUpperCase) //false
mString.lowercased().contains(stringToSearchLowerCase) //true

您不需要为此编写任何定制代码。从1.2版本开始，Swift已经有了所有你需要的方法:

获取字符串长度:count(string); 检查字符串是否包含子字符串:contains(字符串，子字符串); 检查字符串是否以substring开头:startsWith(string, substring) 等。

在Swift 3中

if((a.range(of: b!, options: String.CompareOptions.caseInsensitive, range: nil, locale: nil)) != nil){
    print("Done")
}