Brief introduction to JS operator

Preface ： I'm a freshman, Xiaobai , If there are any mistakes, please point out

Catalog

1. Arithmetic operator

2. Increment and decrement operators

3. Logical operators

 4. Comparison operator

 5. Assignment operator

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1. Arithmetic operator

 1. Add (+) Normal operator

var x = 9;
var y = 8;
var z = x + y;


// The final result is 17

2. reduce (-) Normal operator

var x = 9;
var y = 8;
var z = x - y;


// The final result is 1

3. ride (*) Normal operator

var x = 9;
var y = 8;
var z = x * y;


// The final result is 72

4. except (/) Normal operator

var x = 6;
var y = 2;
var z = x / y;


// The final result is 3

5. Remainder (%) Operator

var x = 7;
var y = 2;
var z = x % y;


// The final result is the remainder 1

2. Increment and decrement operators

1. Pre increment ：   ++num Pre increment , It's self imposed 1, Be similar to num =  num + 1, Abbreviation ++num, Add it first , Then return the value

2. Post increment ：     num++ It's self imposed 1, Be similar to num =  num + 1, Abbreviation num++, Return the original value first , Post autoplus

3. Logical operators

        1. Logic and &&

         On both sides true To return to true, Otherwise return to false

        console.log(true && false) //false;

        console.log(3>2 && 1>2); //false

        alert( 1 && 2 && null && 3 ); // null

        2. Logic or ||

        

         As long as one side is true Both return true, On both sides false When to return to false

        console.log(true ||  false) //true;

        console.log(3>2 ||  1>2); //true

        If one side is true, it is true , The output ture, False output on both sides false

        3. Logic is not ！

         Logic is not （!） It's also called the negation , Used to take a value that is the opposite of a Boolean value , Such as true The opposite of this is false

         var isOk = !true;

         console.log(isOk);  // false

        4. Comparison operator

        <      Less than no.          1<2      true

        >      More than no.          1>2      false

        >=    Greater than or equal to       2>=2   true

        <=     Less than or equal to       3<=2   false

        ==    Whether it is equal or not       2==2   true

        ！=      Unequal sign           3!=2    true

！！ The congruent operator  ===  Operands are not typed , Returns only if the values are equal and the types are equal  true.

             1. Equality operator

console.log(1 == 1);    // true
console.log(1 == 2);    // false
console.log(1 == true); // true
console.log(1 == '1');  // true

             2. Inequality operator

var a = 1;
var b = 2;
var c = '1';

console.log(a != 1);  // false
console.log(a != b);  // true
console.log(a != c);  // false

              3. Greater than operator

console.log(5 > 1);   // true
console.log(5 > 10);  // false
console.log(5 > '5'); // false

               4. Greater than or equal to operator

console.log(5 >= 1);   // true
console.log(5 >= 5);   // true
console.log(5 >= 10);  // false
console.log(5 >= '5'); // true

                5. Less than operator

console.log(5 < 1);   // false
console.log(5 < 5);   // false
console.log(5 < 10);  // true
console.log(5 < '5'); // false

                6. Less than or equal to operator

console.log(5 <= 1);   // false
console.log(5 <= 5);   // true
console.log(5 <= 10);  // true
console.log(5 <= '5'); // true

                7. Inequality operator

var a = 1;
var b = 2;
var c = '1';

console.log(a !== 1);  // false
console.log(a !== b);  // true
console.log(a !== c);  // true

        5. Assignment operator