眼睛大的镜子，日期和时间不是其自身的数据类型，而是名为
strftime()函数用于将日期和时间对象转换为其字符串表示形式。它需要一个或多个格式化代码输入，并返回字符串表示形式。
strftime(format)
格式代码列表：格式代码参考表。
%a
Abbreviated weekday name.
Sun, Mon, …
%A
Full weekday name.
%w
Weekday as a decimal number.
0, 1, …, 6
%d
Day of the month as a zero added decimal.
01, 02, …, 31
%-d
Day of the month as a decimal number.
1, 2, …, 30
%b
Abbreviated month name.
%B
Full month name.
%m
Month as a zero added decimal number.
01, 02, …, 12
%-m
Month as a decimal number.
1, 2, …, 12
%y
Year without century as a zero added decimal number.
00, 01, …, 99
%-y
Year without century as a decimal number.
0, 1, …, 99
%Y
Year with century as a decimal number.
2013, 2019 etc.
%H
Hour (24-hour clock) as a zero added decimal number.
00, 01, …, 23
%-H
Hour (24-hour clock) as a decimal number.
0, 1, …, 23
%I
Hour (12-hour clock) as a zero added decimal number.
01, 02, …, 12
%-I
Hour (12-hour clock) as a decimal number.
1, 2, … 12
%p
Locale’s AM or PM.
AM, dtdqb/p>
%M
Minute as a zero added decimal number.
00, 01, …, 59
%-M
Minute as a decimal number.
0, 1, …, 59
%S
Second as a zero added decimal number.
00, 01, …, 59
%-S
Second as a decimal number.
0, 1, …, 59
%f
Microsecond as a decimal number, zero added on the left.
000000 - 999999
%z
%Z
Time zone name.
%j
Day of the year as a zero added decimal number.
001, 002, …, 366
%-j
Day of the year as a decimal number.
1, 2, …, 366
%U
Week number of the year (Sunday as the first day of the week). All days in a new year preceding the first Sunday are considered to be in week 0.
00, 01, …, 53
%W
Week number of the year (Monday as the first day of the week). All days in a new year preceding the first Monday are considered to be in week 0.
00, 01, …, 53
例：
# Python program to demonstrate
# strftime() function
from datetime import datetime as dt
# Getting current date and time
now = dt.now()
print("Without formatting", now)
# Example 1
s = now.strftime("%a %m %y")
print('nExample 1:', s)
# Example 2
s = now.strftime("%A %-m %Y")
print('nExample 2:', s)
# Example 3
s = now.strftime("%-I %p %S")
print('nExample 3:', s)
# Example 4
s = now.strftime("%-j")
print('nExample 4:', s)
输出：
Without formatting 2019-12-17 18:21:39.211378
Example 1:Tue-12-19
Example 2:Tuesday-12-2019
Example 3:6 PM 39
Example 4:351