Make a number a percentage

问题

What's the best way to strip the "0."XXX% off a number and make it a percentage? What happens if the number happens to be an int?

var number1 = 4.954848;
var number2 = 5.9797;

$(document).ready(function() {    
    final = number1/number2;
    alert(final.toFixed(2) + "%");
});

回答1:

A percentage is just:

(number_one / number_two) * 100

No need for anything fancy:

var number1 = 4.954848;
var number2 = 5.9797;

alert(Math.floor((number1 / number2) * 100)); //w00t!

回答2:

((portion/total) * 100).toFixed(2) + '%'

回答3:

The best solution, where en is the English locale:

fraction.toLocaleString("en", {style: "percent"})

回答4:

Well, if you have a number like 0.123456 that is the result of a division to give a percentage, multiply it by 100 and then either round it or use toFixed like in your example.

Math.round(0.123456 * 100) //12

Here is a jQuery plugin to do that:

jQuery.extend({
    percentage: function(a, b) {
        return Math.round((a / b) * 100);
    }
});

Usage:

alert($.percentage(6, 10));

回答5:

Numeral.js is a library I created that can can format numbers, currency, percentages and has support for localization.

numeral(0.7523).format('0%') // returns string "75%"

numeral.js

回答6:

var percent = Math.floor(100 * number1 / number2 - 100) + ' %';

回答7:

Most answers suggest appending '%' at the end. I would rather prefer Intl.NumberFormat() with { style: 'percent'}

var num = 25;

var option = {
  style: 'percent'

};
var formatter = new Intl.NumberFormat("en-US", option);
var percentFormat = formatter.format(num / 100);
console.log(percentFormat);

回答8:

@xtrem's answer is good, but I think the toFixed and the makePercentage are common use. Define two functions, and we can use that at everywhere.

const R = require('ramda')
const RA = require('ramda-adjunct')

const fix = R.invoker(1, 'toFixed')(2)

const makePercentage = R.when(
  RA.isNotNil,
  R.compose(R.flip(R.concat)('%'), fix, R.multiply(100)),
)

let a = 0.9988
let b = null

makePercentage(b) // -> null
makePercentage(a) // -> 99.88%

来源：https://stackoverflow.com/questions/8522673/make-a-number-a-percentage

标签

javascript

math