常用時間轉換及處理函數：

import datetime

獲取當前時間
d1 = datetime.datetime.now()
print d1
當前時間加上半小時
d2 = d1 + datetime.timedelta(hours=0.5)
print d2
格式化字符串輸出
d3 = d2.strftime('%Y-%m-%d %H:%M:%S')
print d3
將字符串轉化為時間類型
d4 = datetime.datetime.strptime(date,'%Y-%m-%d %H:%M:%S.%f')
print d4</pre>

獲取本周和本月第一天的日期： 

# -- coding:utf-8 --
import datetime
def first_day_of_month():
    '''
    獲取本月第一天
    :return:
    '''


# now_date = datetime.datetime.now()
# return (now_date + datetime.timedelta(days=-now_date.day + 1)).replace(hour=0, minute=0, second=0,
# microsecond=0)
return datetime.date.today() - datetime.timedelta(days=datetime.datetime.now().day - 1)

def first_day_of_week():
    '''
    獲取本周第一天
    :return:
    '''
    return datetime.date.today() - datetime.timedelta(days=datetime.date.today().weekday())
if name == "main":
    this_week = first_day_of_week()
    last_week = this_week - datetime.timedelta(days=7)
    this_month = first_day_of_month()
    last_month = this_month - datetime.timedelta(days=(this_month - datetime.timedelta(days=1)).day)
    print this_week
    print last_week
    print this_month
    print last_month</pre>