Swift 比较运算符

Swift 4支持C语言的所有标准比较运算符。

等于(a == b)
不等于(a != b)
大于(a > b)
小于(a < b)
大于或等于(a >= b)
小于或等于(a <= b)

注意:Swift 4还提供了两个标识符(===和!==)，用于测试两个对象引用是否指向同一个对象实例。

每个比较运算符都返回一个Bool值，用于指定语句是否为真。

1 == 1   // true because 1 is equal to 1  
2 != 1   // true because 2 is not equal to 1  
2 > 1  // true because 2 is greater than 1  
1 < 2  // true because 1 is less than 2  
1 >= 1  // true because 1 is greater than or equal to 1  
2 <= 1  // false because 2 is not less than or equal to 1

比较运算符在条件语句中使用，就像if语句一样。

示例1

let name = "world"  
if name == "world" {  
    print("hello, world")  
} else {  
    print("I am sorry. I don't recognize you")  
}  
// Prints "hello, world", because name is indeed equal to "world".

输出:

hello, world

示例2

let name = "world"  
if name == "JavaTpoint" {  
    print("hello, world")  
} else {  
    print("I am sorry. I don't recognize you")  
}  
// Prints "I am sorry. I don't recognize you", because name is not equal to "world".

输出: