1、数字常量 Number Constant Properties
var biggsetNum = Number.MAX_VALUE;
var smallestNum = Number.MIN_VALUE;
var posInfiniteNum = Number.POSITIVE_INFINITY;
var negInfiniteNum = Number.NEGATIVE_INFINITY;
var notANum = Number.NaN;
console.log('biggsetNum', biggsetNum)
console.log('smallestNum', smallestNum)
console.log('posInfiniteNum', posInfiniteNum)
console.log('negInfiniteNum', negInfiniteNum)
console.log('notANum', notANum)
2、数字类型表示方法
console.log(0b1, 0B11)
console.log(0o7, 0O77)
console.log(0xF, 0XFF)
console.log(123, 123)
console.log(1E3)
console.log(2e-2)
3、数字方法 number method
console.log(Number.parseFloat('1.22'), Number.parseFloat('2.555'), Number.parseFloat(3.99))
console.log(Number.parseInt('1.22'), Number.parseInt('2.555'), Number.parseInt(3.99))
console.log(Number.isFinite(123), Number.isFinite('123'), Number.isFinite(1/0))
console.log(Number.isInteger(2), Number.isInteger('2'), Number.isInteger(2.11))
console.log(Number.isNaN(Number.NaN), Number.isNaN(12))
4、Math 方法 Math Method
console.log(Math.PI)
console.log(Math.abs(-1))
console.log(Math.log2(16))
console.log(Math.log10(100))
console.log(Math.sqrt(2))
console.log(Math.random())
4.1 扩展
for (var i=0; i<3; i++)
console.log(Number.parseInt((Math.random() * 100) + 1 ))
5、算术运算符 Arithmetic operator
console.log(1/2, 2/1, 1/0)
console.log(5%3, 2%3, 9%3)
console.log(parseInt(1/2), parseInt(3/2), parseInt(-1/2), parseInt(-3/2))
console.log(Math.floor(1/2), Math.floor(3/2), Math.floor(-1/2), Math.floor(-3/2))
console.log(Math.ceil(1/2), Math.ceil(3/2), Math.ceil(-1/2), Math.ceil((-3/2)))
console.log(Math.round(1/2), Math.round(3/2), Math.round(-1/2), Math.round(-3/2))
6、位运算 Bit Operations
console.log(1&0, 0&1, 1&1, 0&0)
console.log(1|0, 0|1, 1|1, 0|0)
console.log(1^0, 0^1, 1^1, 0^0)
console.log(~(-2), ~(-1), ~0, ~1, ~2, ~111)
console.log(2<<5, -2<<5)
console.log(64>>5, -64>>5)
7、三元运算符 Ternary operator
console.log((3 > '30')?"True":"False")
console.log((33 > '30')?"True":"False")