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This article will take you through the basic knowledge of operators in JavaScript: arithmetic operators, increment/decrement operators, comparison operators, logical operators and ternary operators. I hope to be helpful.
1 Arithmetic operator
Concept: It is to perform Operators for addition, subtraction, multiplication, and division, and remainder calculations
Operators: , -, *, /, % (remainder operations)
Note: When performing arithmetic operations, floating point (decimal) operations may cause precision problems
2 Increment and decrement operators
Operators:
, --
(a, a--, a, --a)
//前置递增运算符 var num = 1; ++num //或者num++ console.log(num)//结果为2 //++num 相当于是 num = num + 1 //前置++ 是先做自增再做其他运算 //前置递减运算符 var num = 1; --num //或者num-- console.log(num)//结果为0 //--num 相当于是 num = num - 1 //前置-- 是先做自减再做其他运算
3 Comparison operators
Operators: > , 28675c3d02b76e47536b84c673e04c48= , ebb451643671248cfef3bdb32bb50acb , 28675c3d02b76e47536b84c673e04c48= , <= The priority is 6
4 Logical operator
##Logical AND (&&):
var age = 18 var num ; age>18 && (num = 998); //因为 age>18没有成立,逻辑与就已经得到结果为假 //所以当逻辑与计算完毕之后,后面的num=998就不会再运行了
var age = 18; var num; age == 18 || (num = 998); //因为 age==18成立,逻辑或就已经得到结果为真 //所以当逻辑或计算完毕之后,后面的num=998就不会再运行了
Logical NOT (!): Negate true to false, false to true
var a = 5; !(a > 1)//a等于5,所以大于1为真(true),因为取反,所以这个表达式为假(false)5 Ternary operator: ?:
can be understood as a simplified way of writing the double branch of if
Grammar structure:
表达式1 ? 表达式2 : 表达式3
will be executed. When expression 1 is not established, expression 3
var a,b=2,c=3; a=b>2?b:c; //运行结果是a为3,b大于2为真就返回b给a,为假返回c给a,因为b不大于2,所以返回c给a
will be executed. [Recommended learning:
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