JavaScript four numerical rounding methods

One, Math.trunc () 1. Definition

The Math.trunc () method removes the fractional part of a number, preserving the integer portion.

2. Syntax

Math.trunc(value)

3. Example

console.log(Math.trunc(2.01)); // 2console.log(Math.trunc(2.9)); // 2console.log(Math.trunc('0.22')); // 0console.log(Math.trunc(-1.22)); // -1console.log(Math.trunc(-1.56)); // -1console.log(Math.trunc(true)); // 1console.log(Math.trunc(undefined)); // NaN

II, Math.Round () 1. Definition

The Math.Round () method returns the integer part after a number is rounded.

2. Syntax

Math.round(value)

3. Example

console.log(Math.round(2.01)); // 2console.log(Math.round(2.9)); // 3console.log(Math.round('0.22')); // 0console.log(Math.round(-1.22)); // -1console.log(Math.round(-1.56)); // -2console.log(Math.round(true)); // 1console.log(Math.round(undefined)); // NaN

Iii. Math.ceil () 1. Definition

The Math.ceil () method returns the smallest integer greater than or equal to the number, which is rounding up.

2. Syntax

Math.ceil(value)

3. Example

console.log(Math.ceil(2.01)); // 3console.log(Math.ceil(2.9)); // 3console.log(Math.ceil('0.22')); // 1console.log(Math.ceil(-1.22)); // -1console.log(Math.ceil(-1.56)); // -1console.log(Math.ceil(true)); // 1console.log(Math.ceil(undefined)); // NaN

Iv. Math.floor () 1. Definition

The Math.floor () method returns a minimum integer less than or equal to a number, which is rounded down.

2. Syntax

Math.floor(value)

3. Example

console.log(Math.floor(2.01)); // 2console.log(Math.floor(2.9)); // 2console.log(Math.floor('0.22')); // 0console.log(Math.floor(-1.22)); // -2console.log(Math.floor(-1.56)); // -2console.log(Math.floor(true)); // 1console.log(Math.floor(undefined)); // NaN

JavaScript four numerical rounding methods