我如何格式化一个整数到一个特定的长度在JavaScript？ [英] How can I format an integer to a specific length in javascript?

问题描述

我有一个Javascript的数字，我知道是不到10000，也是非负面的。我想显示它作为一个四位数字，与前导零。有什么比以下更优雅？

  if（num <10）num =000+ num; 
 else if（num <100）num =00+ num; 
 else if（num <1000）num =0+ num; 
  

我想要一些内建在Javascript中的东西，但我似乎找不到任何东西。我不认为有什么内置到JavaScript语言来做到这一点。这是一个简单的函数：

$ p $ 函数FormatNumberLength（num，length）{
var r =+ NUM;
while（r.length r =0+ r;
}
return r;



FormatNumberLength（10000，5）输出'10000'
FormatNumberLength（1000，5）输出'01000'
FormatNumberLength（100，5 ）输出'00100'
FormatNumberLength（10，5）输出'00010'


I have a number in Javascript, that I know is less than 10000 and also non-negative. I want to display it as a four-digit number, with leading zeroes. Is there anything more elegant than the following?

if(num<10) num="000"+num;
else if(num<100) num="00"+num;
else if(num<1000) num="0"+num;

I want something that is built into Javascript, but I can't seem to find anything.

解决方案

I don't think there's anything "built" into the JavaScript language for doing this. Here's a simple function that does this:

function FormatNumberLength(num, length) {
    var r = "" + num;
    while (r.length < length) {
        r = "0" + r;
    }
    return r;
}


FormatNumberLength(10000, 5) outputs '10000'
FormatNumberLength(1000, 5)  outputs '01000'
FormatNumberLength(100, 5)   outputs '00100'
FormatNumberLength(10, 5)    outputs '00010'

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