Let’s briefly talk about JavaScript’s Math object method

This article brings you relevant knowledge about javascript, which mainly introduces related issues about the Math object method. The Math object is a built-in object of JavaScript, providing a series of mathematical constants and mathematical Method, this object is not a constructor, so it cannot generate an instance. All properties and methods must be called on the Math object. Let’s take a look at it together. I hope it will be helpful to everyone.

[Related recommendations: javascript video tutorial, web front-end】

The Math object is a built-in JavaScript Object that provides a set of mathematical constants and mathematical methods.

This object is not a constructor, so an instance cannot be generated. All properties and methods must be called on the Math object.

new Math()
// TypeError: object is not a function

The above code indicates that Math cannot be used as a constructor.

Properties

The Math object provides the following read-only mathematical constants.

• E: constant e.

• LN2: The natural logarithm of 2.

• LN10: The natural logarithm of 10.

• LOG2E: The base 2 logarithm of e.

• LOG10E: The base 10 logarithm of e.

• PI: Constant Pi.

• SQRT1_2: The square root of 0.5.

• SQRT2: The square root of 2.

The values ​​of these constants are as follows.

Math.E // 2.718281828459045
Math.LN2 // 0.6931471805599453
Math.LN10 // 2.302585092994046
Math.LOG2E // 1.4426950408889634
Math.LOG10E // 0.4342944819032518
Math.PI // 3.141592653589793
Math.SQRT1_2 // 0.7071067811865476
Math.SQRT2 // 1.4142135623730951

Methods

The Math object provides the following mathematical methods.

round method

The round method is used for rounding.

Math.round(0.1) // 0
Math.round(0.5) // 1

Its operation results for negative values ​​are slightly different from positive values, mainly reflected in the processing of .5.

Math.round(-1.1) // -1
Math.round(-1.5) // -1

abs method, max method, min method

abs method returns the absolute value of the parameter value.

Math.abs(1) // 1
Math.abs(-1) // 1

The max method returns the largest parameter, and the min method returns the smallest parameter.

Math.max(2, -1, 5) // 5
Math.min(2, -1, 5) // -1

floor method, ceil method

The floor method returns the largest integer less than the parameter value.

Math.floor(3.2) // 3
Math.floor(-3.2) // -4

The ceil method returns the smallest integer greater than the parameter value.

Math.ceil(3.2) // 4
Math.ceil(-3.2) // -3

pow method, sqrt method

power method returns the exponential value with the first parameter as the base and the second parameter as the power .

Math.pow(2, 2) // 4
Math.pow(2, 3) // 8

sqrt method returns the square root of the parameter value. If the argument is a negative value, NaN is returned.

Math.sqrt(4) // 2
Math.sqrt(-4) // NaN

log method, exp method

log method returns the natural logarithm value with e as the base.

Math.log(Math.E) // 1
Math.log(10) // 2.302585092994046

To find the logarithm of base 10, you can divide it by Math.LN10; to find the logarithm of base 2, you can divide it by Math.LN2.

Math.log(100)/Math.LN10 // 2
Math.log(8)/Math.LN2 // 3

The exp method returns the parameter power of the constant e.

Math.exp(1) // 2.718281828459045
Math.exp(3) // 20.085536923187668

random method

This method returns a pseudo-random number between 0 and 1, which may be equal to 0, but must be less than 1.

Math.random() // 0.7151307314634323
// 返回给定范围内的随机数
function getRandomArbitrary(min, max) {
  return Math.random() * (max - min) + min;
}
// 返回给定范围内的随机整数
function getRandomInt(min, max) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

Trigonometric function method

The sin method returns the sine of the parameter, the cos method returns the cosine of the parameter, and the tan method returns the tangent of the parameter.

Math.sin(0) // 0
Math.cos(0) // 1
Math.tan(0) // 0

The asin method returns the arc sine of the parameter, the acos method returns the arc cosine of the parameter, and the atan method returns the arc tangent of the parameter. The return values ​​of these three methods are all radian values.

Math.asin(1) // 1.5707963267948966
Math.acos(1) // 0
Math.atan(1) // 0.7853981633974483

[Related recommendations: javascript video tutorial, web front-end】

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