时间模块和随机数模块

时间模块
    时间戳：用秒显示的一个时间段
    两个调用时间模块：1.import time 2.import datetime
    一、time模块重要方法
        1.time.time() #重要*：时间戳*
            print(time.time())#1548748325.4074776：时间戳
        2.time.clock() #cpu执行时间*
            time.sleep(3)
            print(time.clock())
            #计算机cpu执行时间DeprecationWarning: time.clock has been deprecated in Python 3.3 and will be removed from Python 3.8: use time.perf_counter or time.process_time instead print(time.clock())
            #意思是在python3.8里将被弃用
        3.time.gmtime() #结构化时间*
            print(time.gmtime())
            #time.struct_time(tm_year=2019, tm_mon=1, tm_mday=29, tm_hour=8, tm_min=10, tm_sec=30, tm_wday=1, tm_yday=29, tm_isdst=0)
        4.time.localtime() #计算机时间*
            print(time.localtime())
            #time.struct_time(tm_year=2019, tm_mon=1, tm_mday=29, tm_hour=16, tm_min=18, tm_sec=33, tm_wday=1, tm_yday=29, tm_isdst=0)
        5.time.strftime() #字符串时间*
            print(time.strftime('%Y--%m--%d %H:%M:%S'))
            %Y  Year with century as a decimal number.
            %m  Month as a decimal number [01,12].
            %d  Day of the month as a decimal number [01,31].
            %H  Hour (24-hour clock) as a decimal number [00,23].
            %M  Minute as a decimal number [00,59].
            %S  Second as a decimal number [00,61].
            %z  Time zone offset from UTC.
            %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.
            %I  Hour (12-hour clock) as a decimal number [01,12].
            %p  Locale's equivalent of either AM or PM.
        6.time.strptime() #把time.strftime()类时间转化成结构化时间
            print(time.strptime('2019--01--29 16:28:04','%Y--%m--%d %H:%M:%S'))
            #time.struct_time(tm_year=2019, tm_mon=1, tm_mday=29, tm_hour=16, tm_min=28, tm_sec=4, tm_wday=1, tm_yday=29, tm_isdst=-1)
            a=time.strptime('2019--01--29 16:28:04','%Y--%m--%d %H:%M:%S')
            print(a.tm_year)#单独取出年份
            print(a.tm_mday)#单独取出日
        7.time.ctime() #打印当前时间（格式是固定的无法更改，括号中可以加参数）*
            print(time.ctime())
            print(time.ctime(123456))#参数加一个时间戳
        8.time.mktime() #参数加结构化时间*
            print(time.mktime(time.localtime()))#把当前时间转化为时间戳（秒）
    二、表示时间三种方式：1.时间戳 2.结构化时间 3.格式化时间
    三、datetime模块：
        datetime.now()#现在时间*
            print(datetime.datetime.now())
随机数模块
    调用随机数模块：import random
    1.random.random()#0-1间的随机数
        print(random.random())
    2.random.rand()#可规定范围的随机整数
        print(random.randint(1,8))#1-8间的随机整数（包括8）
    3.random.choice('hello')#范围内随机字符或序列
        print(random.choice('hello'))
        print(random.choice(['123',4,[1,2]]))
    4.random.sample()#随机选多个
        print(random.sample(['123',4,[1,2],4,5],2))#序列中随机选两个
    3.random.randrange()#范围内随机生成，不包含末尾
        print(random.randrange(1,3))#不包含3
        例：
        方法一：（有缺陷）
            import random
            #print(random.sample(['123',4,[1,2],4,5],2))
            #print(random.randrange(1,3))#不包含3
            def yzm():
                c = ''
                for i in range(5):
                    if i==random.choice(0,5):
                        add=random.randrange(10)
                    else:
                        add=chr(random.randrange(65,91))
                    c+=str(add)
                print(c)
            yzm()
        方法二：（完整简单）
            import random
            #print(random.sample(['123',4,[1,2],4,5],2))
            #print(random.randrange(1,3))#不包含3
            def yzm():
                c = ''
                for i in range(5):
                    add=random.choice([random.randrange(10),chr(random.randrange(65,91))])
                    # if i==random.choice(0,5):
                    #     add=random.randrange(10)
                    # else:
                    #     add=chr(random.randrange(65,91))
                    c+=str(add)
                print(c)
            yzm()