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개발언어

JavaScript Format (자바스크립트 포멧)

by 엔돌슨 2008. 3. 5.
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Overview of formatting numbers in JavaScript

JavaScript doesn't have many built-in methods to format numbers. Most of the time customized code needs to be used. Refer below for a couple rounding methods that JavaScript offers, then next up is some custom code I wrote to do more advanced formatting.
자바스크립트 포멧형을 찾았다. 숫자의 자리수나 소수자리 등을 지정하는 방법이 있다.
내가 정작 원하는 건 string.Format 같은것이 였는 데 없다.
javascript 도 분명히 있을텐데... 이상타.
그냥 하나 만들었다.

if ( str.length == 1 ) {  str = '0' + str;  }
무식하지만 format("0#", str)과 같은 혀과를 보여준다 ㅎㅎ

Round to a certain number of places

For rounding decimals you can use the built-in JavaScript methods toFixed or toPrecision.

var num = 10;
var result = num.toFixed(2); // result will equal 10.00

num = 930.9805;
result = num.toFixed(3); // result will equal 930.981

num = 500.2349;
result = num.toPrecision(4); // result will equal 500.2

num = 5000.2349;
result = num.toPrecision(4); // result will equal 5000

num = 555.55;
result = num.toPrecision(2); // result will equal 5.6e+2

Learn more

Add commas

This functionality is not built into JavaScript, so custom code needs to be used. The following is one way of adding commas to a number, and returning a string.

function addCommas(nStr)
{
	nStr += '';
	x = nStr.split('.');
	x1 = x[0];
	x2 = x.length > 1 ? '.' + x[1] : '';
	var rgx = /(\d+)(\d{3})/;
	while (rgx.test(x1)) {
		x1 = x1.replace(rgx, '$1' + ',' + '$2');
	}
	return x1 + x2;
}

Learn more

Multi-functional number format script

  • commas (configurable digit grouping separators and decimal symbols)
  • certain decimal precision that leave trailing zeros
  • various formats for currency and negative values
  • input can be a string that's already formatted

Learn more

Interactive example

Syntax information

Comments? Questions?

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