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  • day16

    一 time与datetime模块

    在Python中,通常有这几种方式来表示时间:

    • 时间戳(timestamp):通常来说,时间戳表示的是从1970年1月1日00:00:00开始按秒计算的偏移量。我们运行“type(time.time())”,返回的是float类型。
    • 格式化的时间字符串(Format String)
    • 结构化的时间(struct_time):struct_time元组共有9个元素共九个元素:(年,月,日,时,分,秒,一年中第几周,一年中第几天,夏令时)
    1 import time
    2 #--------------------------我们先以当前时间为准,让大家快速认识三种形式的时间
    3 print(time.time()) # 时间戳:1487130156.419527
    4 print(time.strftime("%Y-%m-%d %X")) #格式化的时间字符串:'2017-02-15 11:40:53'
    5 
    6 print(time.localtime()) #本地时区的struct_time
    7 print(time.gmtime())    #UTC时区的struct_time
    %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.
    复制代码
    %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.
    复制代码

    其中计算机认识的时间只能是'时间戳'格式,而程序员可处理的或者说人类能看懂的时间有: '格式化的时间字符串','结构化的时间' ,于是有了下图的转换关系

     1 #--------------------------按图1转换时间
     2 # localtime([secs])
     3 # 将一个时间戳转换为当前时区的struct_time。secs参数未提供,则以当前时间为准。
     4 time.localtime()
     5 time.localtime(1473525444.037215)
     6 
     7 # gmtime([secs]) 和localtime()方法类似,gmtime()方法是将一个时间戳转换为UTC时区(0时区)的struct_time。
     8 
     9 # mktime(t) : 将一个struct_time转化为时间戳。
    10 print(time.mktime(time.localtime()))#1473525749.0
    11 
    12 
    13 # strftime(format[, t]) : 把一个代表时间的元组或者struct_time(如由time.localtime()和
    14 # time.gmtime()返回)转化为格式化的时间字符串。如果t未指定,将传入time.localtime()。如果元组中任何一个
    15 # 元素越界,ValueError的错误将会被抛出。
    16 print(time.strftime("%Y-%m-%d %X", time.localtime()))#2016-09-11 00:49:56
    17 
    18 # time.strptime(string[, format])
    19 # 把一个格式化时间字符串转化为struct_time。实际上它和strftime()是逆操作。
    20 print(time.strptime('2011-05-05 16:37:06', '%Y-%m-%d %X'))
    21 #time.struct_time(tm_year=2011, tm_mon=5, tm_mday=5, tm_hour=16, tm_min=37, tm_sec=6,
    22 #  tm_wday=3, tm_yday=125, tm_isdst=-1)
    23 #在这个函数中,format默认为:"%a %b %d %H:%M:%S %Y"。

    1 #--------------------------按图2转换时间
    2 # asctime([t]) : 把一个表示时间的元组或者struct_time表示为这种形式:'Sun Jun 20 23:21:05 1993'。
    3 # 如果没有参数,将会将time.localtime()作为参数传入。
    4 print(time.asctime())#Sun Sep 11 00:43:43 2016
    5 
    6 # ctime([secs]) : 把一个时间戳(按秒计算的浮点数)转化为time.asctime()的形式。如果参数未给或者为
    7 # None的时候,将会默认time.time()为参数。它的作用相当于time.asctime(time.localtime(secs))。
    8 print(time.ctime())  # Sun Sep 11 00:46:38 2016
    9 print(time.ctime(time.time()))  # Sun Sep 11 00:46:38 2016
    1 #--------------------------其他用法
    2 # sleep(secs)
    3 # 线程推迟指定的时间运行,单位为秒。
    #时间加减
    import datetime
    
    # print(datetime.datetime.now()) #返回 2016-08-19 12:47:03.941925
    #print(datetime.date.fromtimestamp(time.time()) )  # 时间戳直接转成日期格式 2016-08-19
    # print(datetime.datetime.now() )
    # print(datetime.datetime.now() + datetime.timedelta(3)) #当前时间+3天
    # print(datetime.datetime.now() + datetime.timedelta(-3)) #当前时间-3天
    # print(datetime.datetime.now() + datetime.timedelta(hours=3)) #当前时间+3小时
    # print(datetime.datetime.now() + datetime.timedelta(minutes=30)) #当前时间+30分
    
    
    #
    # c_time  = datetime.datetime.now()
    # print(c_time.replace(minute=3,hour=2)) #时间替换

    二 random模块

     
     1 import random
     2  
     3 print(random.random())#(0,1)----float    大于0且小于1之间的小数
     4  
     5 print(random.randint(1,3))  #[1,3]    大于等于1且小于等于3之间的整数
     6  
     7 print(random.randrange(1,3)) #[1,3)    大于等于1且小于3之间的整数
     8  
     9 print(random.choice([1,'23',[4,5]]))#1或者23或者[4,5]
    10  
    11 print(random.sample([1,'23',[4,5]],2))#列表元素任意2个组合
    12  
    13 print(random.uniform(1,3))#大于1小于3的小数,如1.927109612082716 
    14  
    15  
    16 item=[1,3,5,7,9]
    17 random.shuffle(item) #打乱item的顺序,相当于"洗牌"
    18 print(item)
     
    import random
    def make_code(n):
        res=''
        for i in range(n):
            s1=chr(random.randint(65,90))
            s2=str(random.randint(0,9))
            res+=random.choice([s1,s2])
        return res
    
    print(make_code(9))
    复制代码
    import random
    def make_code(n):
        res=''
        for i in range(n):
            s1=chr(random.randint(65,90))
            s2=str(random.randint(0,9))
            res+=random.choice([s1,s2])
        return res
    
    print(make_code(9))
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  • 原文地址:https://www.cnblogs.com/hui2002/p/10071210.html
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