如何在 Python 3 中用前导零填充字符串
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How to pad a string with leading zeros in Python 3
提问by Gabby Freeland
I'm trying to make length = 001in Python 3 but whenever I try to print it out it truncates the value without the leading zeros (length = 1). How would I stop this happening without having to cast lengthto a string before printing it out?
我正在尝试length = 001在 Python 3 中制作，但是每当我尝试将其打印出来时，它都会截断没有前导零 ( length = 1)的值。我将如何阻止这种情况发生而不必length在打印出来之前转换为字符串？
回答by nyedidikeke
Make use of the zfill()helper method to left-pad any string, integer or float with zeros; it's valid for both Python 2.xand Python 3.x.
使用zfill()辅助方法左填充任何字符串、整数或浮点数为零；它对Python 2.x和Python 3.x都有效。
Sample usage:
示例用法：
print str(1).zfill(3);
# Expected output: 001
Description:
描述：
When applied to a value, zfill()returns a value left-padded with zeros when the length of the initial stringvalue less than that of the applied widthvalue, otherwise, the initial stringvalue as is.
当应用于一个值时，zfill()当初始字符串值的长度小于应用的宽度值的长度时，返回一个用零填充的值，否则返回初始字符串值。
Syntax:
句法：
str(string).zfill(width)
# Where string represents a string, an integer or a float, and
# width, the desired length to left-pad.
回答by PhE
Since python 3.6 you can use fstring :
从 python 3.6 开始，您可以使用 fstring ：
>>> length = 1
>>> print(f'length = {length:03}')
length = 001
回答by Blckknght
Python integers don't have an inherent length or number of significant digits. If you want them to print a specific way, you need to convert them to a string. There are several ways you can do so that let you specify things like padding characters and minimum lengths.
Python 整数没有固有长度或有效位数。如果您希望它们以特定方式打印，则需要将它们转换为字符串。有多种方法可以让您指定填充字符和最小长度等内容。
To pad with zeros to a minimum of three characters, try:
要将零填充到至少三个字符，请尝试：
length = 1
print(format(length, '03'))
回答by Anatol
There are many ways to achieve this but the easiest way in Python 3.6+, in my opinion, is this:
有很多方法可以实现这一点，但在我看来，Python 3.6+ 中最简单的方法是：
print(f"{1:03}")
回答by wydadman
I suggest this ugly method but it works:
我建议使用这种丑陋的方法，但它有效：
length = 1
lenghtafterpadding = 3
newlength = '0' * (lenghtafterpadding - len(str(length))) + str(length)
I came here to find a lighter solution than this one!
我来这里是为了找到比这个更轻松的解决方案！
