python时间模块和random模块

模块：用一坨代码实现了某个功能的代码集合。

类似于函数式编程和面向过程编程，函数式编程则完成一个功能，其他代码用来调用即可，提供了代码的重用性和代码间的耦合。而对于一个复杂的功能，可能需要多个函数才能完成（函数又可以在不同的.py文件中），n个.py文件组成的代码集合就成为模块。

如：os是系统相关的模块；file是文件操作相关的模块。

模块分为三种：自定义模块、内置标准模块（又称标准库）、开源模块

time&datetime模块

#!/usr/bin/env python
#-*- coding:utf-8 -*-
#Author: Tony Cabel

import time,datetime
print(time.clock())         #返回处理器时间,3.3开始已废弃 , 改成了time.process_time()
                            # 测量处理器运算时间,不包括sleep时间,不稳定,mac上测不出来
print(time.altzone/3600)    #打印时区
print(time.asctime())       #返回时间格式"Mon Feb 20 15:01:02 2017",
t=time.localtime()          #返回本地时间 的struct time对象格式
print(time.localtime(time.time()+3*3600))   #本地时间后三个小时的时间
print(t)
print(t.tm_year,t.tm_yday)
print(time.time())          #时间戳，从1970年一月一日至今的秒数
print(time.gmtime())        #返回UTC时间
print(time.ctime())         #返回Fri Aug 19 12:38:29 2016 格式,
t2=time.strptime("2017-2-20 11:30","%Y-%m-%d %H:%M")    #将 日期字符串 转成 struct时间对象格式
t2_stamp=time.mktime(t2)            #将struct时间对象转成时间戳
print(t2)
t3=time.localtime(t2_stamp)         #将本地时间戳转换成struct_time格式
t3_str=time.strftime("%Y-%m-%d-%H-%M.log",t3)      #将utc struct_time格式转成指定的字符串格式
print(t3_str)
t4=datetime.datetime.now()          #返回当前时间，格式：2017-02-20 15:01:02.487076
print(t4)
t4_fr=t4-datetime.timedelta(days=3) #返回三天前的这个时候的时间，也可以小时分钟秒
print(t4_fr)
print(t4.replace(year=2016,month=3,hour=12))    #将当前时间进行任意替换

时间转换路径：

 

Directive	Meaning	Notes
%a	Locale’s abbreviated weekday name.
%A	Locale’s full weekday name.
%b	Locale’s abbreviated month name.
%B	Locale’s full month name.
%c	Locale’s appropriate date and time representation.
%d	Day of the month as a decimal number [01,31].
%H	Hour (24-hour clock) as a decimal number [00,23].
%I	Hour (12-hour clock) as a decimal number [01,12].
%j	Day of the year as a decimal number [001,366].
%m	Month as a decimal number [01,12].
%M	Minute as a decimal number [00,59].
%p	Locale’s equivalent of either AM or PM.	(1)
%S	Second as a decimal number [00,61].	(2)
%U	Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.	(3)
%w	Weekday as a decimal number [0(Sunday),6].
%W	Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0.	(3)
%x	Locale’s appropriate date representation.
%X	Locale’s appropriate time representation.
%y	Year without century as a decimal number [00,99].
%Y	Year with century as a decimal number.
%z	Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59].
%Z	Time zone name (no characters if no time zone exists).
%%	A literal '%' character.

random模块

import random
print(random.random())      #打印一个随机小数，小数点后十六位
print(random.randint(1,3))  #随机打印一个从1到3的数，包括3
print(random.randrange(1,10)) #在range范围内打印一个随机数

import string
src=string.ascii_letters+string.digits      #生成随机密码的一种方式
print(''.join(random.sample(src,6)))

checkcode=''                    #另一种生成随机验证码方式
for i in range(6):
    current=random.randint(0,6)
    if current != i:
        temp=chr(random.randint(65,90))
    else:
        temp=random.randint(0,9)
    checkcode+=str(temp)
print(checkcode)

备注：用random.sample不会生成重复的字符，也就是说第一种方式生成的验证码中不会有重复的字符，而第二种方式生成的可能会有重复的字符。