所有这些都创建了字符串“01”:

>python -m timeit "'{:02d}'.format(1)"
1000000 loops, best of 5: 357 nsec per loop

>python -m timeit "'{0:0{1}d}'.format(1,2)"
500000 loops, best of 5: 607 nsec per loop

>python -m timeit "f'{1:02d}'"
1000000 loops, best of 5: 281 nsec per loop

>python -m timeit "f'{1:0{2}d}'"
500000 loops, best of 5: 423 nsec per loop

>python -m timeit "str(1).zfill(2)"
1000000 loops, best of 5: 271 nsec per loop

>python
Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AMD64)] on win32

python的方法是:

str(number).rjust(string_width, fill_char)

这样，如果原始字符串的长度大于string_width，则原始字符串将原封不动地返回。例子:

a = [1, 10, 100]
for num in a:
    print str(num).rjust(2, '0')

结果:

01
10
100

如果处理的数字是一位数或两位数:

‘0’+ str (number)黑帽子-2:铝还是‘0那0’.format (number)黑-2:铝

x = [1, 10, 100]
for i in x:
    print '%02d' % i

结果:

01
10
100

在文档中阅读有关使用%格式化字符串的更多信息。

width = 5
num = 3
formatted = (width - len(str(num))) * "0" + str(num)
print formatted

你可以使用str.zfill:

print(str(1).zfill(2))
print(str(10).zfill(2))
print(str(100).zfill(2))

打印:

01
10
100