不支持的格式字符'm'

Question

I am trying to convert now.month to decimal so it would look like 01 and not like 1. The code is:

import datetime
now = datetime.datetime.now()
monthstr = ".%m" % now.month

it works in this line with %d

daystr = "file_%d" % now.day

the error I get is

ValueError: unsupported format character 'm' (0x6d) at index 2

I also tried with the new type {:%m}. The error is the same. Do i miss any libraries? Or is there another way except adding 0 to months from Jan to September

Python v.3.6.3

Answer 1

This is because %d do not stands for days . It stands for digits and is a placeholder for numbers when using string formatting.

You should use it for months also.

monthstr = ".%d" % now.month

Since you want the format as 01 and not like 1 , use @user3483203 answer .

Answer 2

You are using string formatting like datetime formatting here. String formatting has its own "mini-language" , and m is not a valid symbol in this language.

For your purposes, it would be better to use strftime

>>> now.strftime('.%m')
'.07'