JavaScript 格式编号，始终为 3 位数字
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JavaScript format number to day with always 3 digits
提问by ali
Possible Duplicate:
How can I create a Zerofilled value using JavaScript?
I have to output a day number that must always have 3 digits. Instead of 3it must write 003, instead of 12it must write 012. If it is greater than 100output it without formatting. I wonder if there's a regex that I could use or some quick in-line script, or I must create a function that should do that and return the result. Thanks!
我必须输出一个必须始终为 3 位数字的日期编号。而不是3，必须写003，而不是12必须写012。如果大于100则不格式化输出。我想知道是否有我可以使用的正则表达式或一些快速的内联脚本，或者我必须创建一个应该这样做并返回结果的函数。谢谢！
回答by georg
How about:
怎么样：
zeroFilled = ('000' + x).substr(-3)
For arbitrary width:
对于任意宽度：
zeroFilled = (new Array(width).join('0') + x).substr(-width)
As per comments, this seems more accurate:
根据评论，这似乎更准确：
lpad = function(s, width, char) {
return (s.length >= width) ? s : (new Array(width).join(char) + s).slice(-width);
}
回答by Mattias Buelens
I found an elegant solution by Samuel Mullen on his blog. I simply optimized the zeroescreation.
我在 Samuel Mullen的博客上找到了一个优雅的解决方案。我只是优化了zeroes创作。
function lpad(value, padding) {
var zeroes = new Array(padding+1).join("0");
return (zeroes + value).slice(-padding);
}
Usage: lpad(12, 3)results in "012"
用法：lpad(12, 3)结果"012"
回答by Mattias Buelens
You can do this...
你可以这样做...
("00" + day).slice(-3)
It'll prepend the zeros, and then .slice()will always give you the last 3 values of the string.
它会在前面加上零，然后.slice()总是给你字符串的最后 3 个值。
回答by Samuel Rossille
I would write the following function:
我会编写以下函数：
var pad = function(n, length) {
var str = "" + n;
if(str.length < length) str = new Array(length - str.length).join("0") + str;
return str;
};
回答by ThiefMaster
Here is a simple function that pads a number with zeroes to a certain width:
这是一个简单的函数，它用零填充一个数字到一定的宽度：
function zeroFill(number, width) {
width -= number.toString().length;
if(width > 0) {
return new Array(width + (/\./.test(number) ? 2 : 1)).join('0') + number;
}
return number + ""; // always return a string
}
(from How can I pad a value with leading zeros?)
（来自如何用前导零填充值？）
Since the original answer did not explain how the function works I'll do it here.
由于原始答案没有解释该函数的工作原理，我将在这里进行。
widthinitially contains the total length you want, so width - number_of_digitsis the number of padding chars necessary.new Array(len + 1).join(str)repeats strlentimes.
The regex is used to add an additional padding zero in case of a number containing a decimal point since the point was also included in the number_of_digitsdetermined using number.toString().length
width最初包含您想要的总长度，因此width - number_of_digits需要填充字符的数量。new Array(len + 1).join(str)重复strlen次数。
正则表达式用于在包含小数点的数字的情况下添加额外的填充零，因为该点也包含在number_of_digits确定的使用中number.toString().length
回答by VisioN
One possible solution:
一种可能的解决方案：
?while ((val+"").length < 3?) {
val = "0" + val;
}
