初学 Python — 处理日期与时间[0]

4000

一、寻找2013年与2014今日之前（包括今日）年所有的星期五

import datetime
import calendar
today = datetime.date.today()
oneday = datetime.timedelta(days=1)
while today.year == 2014 or today.year == 2013:
if today.weekday()==4:
print(today.strftime('%A, %d-%b-%Y'))
today = today-oneday*7
else:
today -= oneday

*注意

1  today.year,today.month,today.day,today.weekday()返回的都是int型，其中weekday()的周一到周日分别以0-6表示。

2  默认日期格式是2014-03-04

3  切不可使用这种循环 while today.year==2014 or 2013。同时Python逻辑运算符号没有||，&&一说。

4  如果要寻找某年的某月的星期X，则定义以下函数（不考虑鲁棒性）

import datetime
import calendar
def FindWeekday(year,month,weekday):
oneday = datetime.timedelta(days=1)
if month == 0:
fristday = datetime.date(year,1,1)
while fristday.year == year:
if fristday.weekday()==weekday-1:
print(fristday.strftime('%A, %d-%b-%Y'))
fristday += oneday*7
else:
fristday += oneday
else:
fristday = datetime.date(year,month,1)
while fristday.year == year and fristday.month == month:
if fristday.weekday()==weekday-1:
print(fristday.strftime('%A, %d-%b-%Y'))
fristday += oneday*7
else:
fristday += oneday

5  为了能够随时调用4中函数，我们将其存储到C:/MyPython目录下，建立新文件，载入该模块

import sys
sys.path.append("C:\MyPython")  #将目标路径加入到Python搜索路径中去
import FindWeekDay #或者 from MyPython import <span style="font-family: Arial, Helvetica, sans-serif;">FindWeekDay </span>

这时，如果直接调用

FindWeekDay（2013,1,3）

将会报错，TypeError: 'module' object is not callable

需加入模块名限定即可

FindWeekDay.FindWeekDay（2013,1,3）

运行结果如下

Wednesday, 02-Jan-2013
Wednesday, 09-Jan-2013
Wednesday, 16-Jan-2013
Wednesday, 23-Jan-2013
Wednesday, 30-Jan-2013