JS foundation 5

Math

Math Object as a storage mathematical formula , Information and Computing

attribute

attribute	Method
Math.E	Base of natural logarithm e Value
Math.LN10	With 10 The natural logarithm of the base
Math.LOG2E	With 2 Bottom e The logarithmic
Math.PI	π Value
Math.max()	Maximum
Math.min()	minimum value
Math.ceil()	Rounding up
Math.floor()	Rounding down
Math.round()	Round to the nearest whole
Math.fround()	Return to the nearest （32 position ） Floating point value
Math.random()	0~1 Between random numbers
Math.abs()	Return the absolute value
Math.log()	Return to the natural logarithm

notes ：
Math.random() Random number but excluding 1
Built in Math The operation is faster than custom functions

Base number

Integers can be expressed in octal or hexadecimal literal

1. Octal must be preceded by 0

var num=016
console.log(num)
// result 14
var num=019
console.log(num)
// Invalid octal 10 Base number 19 Handle 

2. Hexadecimal must be preceded by 0x( Case sensitive )

var num=0x16
console.log(num)
// result 22

parseInt() It can recognize the value of different base numbers

notes ：parseFloat() Only decimal numbers can be parsed

1. 0 The following values will be interpreted as octal

var num=parseInt(016)
console.log(num)
// result 14

2. 0x The values that follow are interpreted as hexadecimal

var num=parseInt(0x16)
console.log(num)
// result 22

toString() It can return numbers in different hexadecimals by passing in parameters

var num=16
        console.log(num.toString())
        // result 16
        console.log(num.toString(2))
        // result 10000
        console.log(num.toString(8))
        // result 20
        console.log(num.toString(10))
        // result 16
        console.log(num.toString(16))
        // result 10