Swift 比較運算符

Swift 4支持C語言的所有標準比較運算符。愛掏網 - it200.com

• 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還提供了兩個標識符(===和!==)，用于測試兩個對象引用是否指向同一個對象實例。愛掏網 - it200.com

每個比較運算符都返回一個Bool值，用于指定語句是否為真。愛掏網 - it200.com

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  

比較運算符在條件語句中使用，就像if語句一樣。愛掏網 - it200.com

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".  

輸出:

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".  

輸出:

I am sorry. I don't recognize you