Number新增方法
{
let num = 123;
let num1 = NaN;
let str = "123";
console.log(Number.isNaN(num));//false
console.log(Number.isNaN(num1));//true
console.log(Number.isNaN(str));//false
// 只跟值是不是NaN有關(guān)系窥淆，與數(shù)據(jù)類型無關(guān)
}
{
let num='1234,5a';//舍去小數(shù)位
console.log(Number.parseInt(num));
}
- .parseFloat()瓢宦，轉(zhuǎn)成標(biāo)準(zhǔn)的小數(shù)，將多余的0去掉
{
let num1 = 1234.213120000000;//1234.21312
console.log(Number.parseFloat(num1));
}
- .isInteger()肌括，判斷是不是整數(shù)
{
let num2 = 123;//true
let num3 = 123.12;//false
console.log(Number.isInteger(num2));
console.log(Number.isInteger(num3));
}
計(jì)算次方
math.pow(num,次方)
開平方
math.sqrt(num);
開立方
math.cbrt(num);
判斷一個(gè)數(shù)是不是整數(shù)
math.sign()
正數(shù)返回1
負(fù)數(shù)返回-1
0返回0
- 新增運(yùn)算符 ** 指數(shù)運(yùn)算，相當(dāng)于math.pow();
console.log(2 ** 2);
console.log(3 ** 3);
console.log(4 ** 4);
console.log(5 ** 5);
