如果您的部分代码需要String,则类型安全可以防止您错误地传递给Int。同样,类型安全可防止您意外地将可选String传递给需要非可选String的代码。类型安全可帮助您在开发过程中尽早捕获和修复错误。 常量和变量(Constants and Variables) 常量和变量将名称(如maximumNumberOfLoginAttempts或welcomeMessage)与特定类型的值(如数...
varstringSet:Set=["11","22","33","44"]stringSet.remove("11") 要检查集合是否包含了特定的元素,使用 contains(_:)方法。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 varstringSet:Set=["11","22","33","44"]ifstringSet.contains("11"){print("包含")}//输出:包含 遍历集合 你可以...
let numbers = [1, 2, 3, 4, 5] let number = numbers.last(where: { $0 > 2 }) print(number!) // 输出: 5 3、判断是否包含满足条件的元素 let numbers = [1, 2, 3, 4, 5] let isContains = numbers.contains(where: { $0 > 2 }) print(isContains) // 输出: true 4、查找满足条...
"""// 字符串插值letmultiplier=3letmessage="\(multiplier)times 2.5 is\(Double(multiplier)*2.5)"// message 是 "3 times 2.5 is 7.5"// 计算字符数量varword="cafe"print("the number of characters in\(word)is\(word.count)")// 打印输出“the number of characters in cafe is 4”varemptyStri...
你可以创建一个容纳 Int 值的数组,或者容纳String 值的数组,甚至容纳任何 Swift 可以创建的其他类型的数组。同样,你可以创建一个存储任何指定类型值的字典,而且类型没有限制。 2. 泛型解决的问题 下面的 swapTwoInts(_:_:) 是一个标准的非泛型函数,用于交换两个 Int 值: ...
return String(self[..<sInde]) } /// 截取人任意位置到结束 /// /// - Parameter end: /// - Returns: 截取后的字符串 func stringCutToEnd(star: Int) -> String { if !(star < count) { return "截取超出范围" } let sRang = index(startIndex, offsetBy: star)..<endIndex ...
/// ("not a number"). /// /// The given string may begin with a plus or minus sign character (`+` or /// `-`). The allowed formats for each of these representations is then as /// follows: /// /// - A *decimal value* contains the significand, a sequence of decimal ...
[String:Any] {if letnumber = dictionary["someKey"]as?Double{// access individual value in dictionary}for(key, value)indictionary {// access all key / value pairs in dictionary}if letnestedDictionary = dictionary["anotherKey"]as? [String:Any] {// access nested dictionary values by key} ...
address")}SecRandomCopyBytes(kSecRandomDefault,64,baseAddress)}// Add the encryption key to the config and open the realmletconfig=Realm.Configuration(encryptionKey:key)letrealm=tryRealm(configuration:config)// Use the Realm as normalletdogs=realm.objects(Dog.self).filter("name contains 'Fido'"...
let numbers = [1, 2, 3, 4, 5] let number = numbers.last(where: { $0 > 2 }) print(number!) // 输出: 5 3、判断是否包含满足条件的元素 let numbers = [1, 2, 3, 4, 5] let isContains = numbers.contains(where: { $0 > 2 }) print(isContains) // 输出: true 4、查找满足...