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JavaScript built-in object Math example sharing

Author：Eve Cole Update Time：2022-06-11 13:11:59
This article brings you relevant knowledge about the JavaScript built-in object math. It explains the usage of common functions in Math based on examples, including the absolute value method, three rounding methods, etc. Let’s take a look at it together. I hope Helpful to everyone.

[Related recommendations: JavaScript video tutorials, web front-end]

Math Overview

The Math object is not a constructor, it has the properties and methods of mathematical constants and functions. Math-related operations (absolute value, rounding, maximum value, etc.) can use members in Math.

Usage of commonly used functions in Math

  • Math.PI //Pi

  • Math.floor () //Rounding down

  • Math.ceil () //Rounding up

  • Math.round () //Rounding to the nearest integer Note - 3.5 The result is - 3

  • Math.abs () //Absolute value

  • Math.max ()/Math.min() //Find the maximum and minimum values

  • ​​Math.random() //Return a random decimal 0=<x<1(this method There are no parameters in it)

1. Absolute value method

//1. Absolute value method console.log(Math.abs(1)); // 1
        console.log(Math.abs(-1)); //1
        console.log(Math.abs('-5')); //5 will be implicitly converted, convert the numeric string into a number, and then take the absolute value console.log(Math.abs('aniu')); / /NaN

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2. Three rounding methods

//2. Three rounding methods console.log(Math.floor(1.1)); //1
        console.log(Math.floor(1.9)); //1
        console.log(Math.floor(-1.1)); //-2

        console.log(Math.ceil(1.1)); // 2
        console.log(Math.ceil(1.9)); //2
        console.log(Math.ceil(-1.9)); //-1

        console.log(Math.round(1.5)); //2 This special rounding of .5 is to take the larger console.log(Math.round(-1.5)); // -1 to take the console.log to the larger one. (Math.round(-1.2)); // -1

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3. Find the maximum/minimum value

//3. Find the maximum/minimum value console.log(Math.max(1,5,78,46));
        console.log(Math.min(1,5,78,46));

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4. Random number

//4. Random number console.log(Math.random());

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Case - A small algorithm to find a random integer between two numbers (important)

Find a random integer between two numbers and contain these two numbers:
//core algorithm
Math.floor(Math.random()*(max-min)) + min;

function getRandom(min,max){
            return Math.floor(Math.random()*(max-min)) + min;
        }

        console.log(getRandom(1,7));

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Case - random roll call (hehehe)

//Random roll call var arr = ['Aniu','Mengmeng','Little Naruto','winter','Xiao He','WA','Bit God', 'Zawa'] //Too many, just write these examples console.log(arr);
  console.log('Aniu loves you???');
  function getRandom(min,max){
          return Math.floor(Math.random()*(max-min)) + min;
       }

  console.log('Random point hit:' + arr[getRandom(0,arr.length - 1)]);

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[Related recommendations: JavaScript video tutorials, web front-end]

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