Python_ Common built-in modules

One, Time module (Timing module):

Three ways to represent time:

In Python, there are usually three ways to represent time: timestamp, tuple (struct_time), formatted time string:

(1) timestamp (timestamp): Typically, a timestamp represents an offset that is calculated in seconds, starting January 1, 1970 00:00:00. We run "type (Time.time ())" and return the float type.

(2) formatted time string (format string): ' 1995-10-04 '

%y Two-digit year representation (00-99)%Y Four-digit year representation (000-9999)%m Month (01-12)One day in%d months (0-31)%H 24-hour hours (0-23)%I 12-hour hours (01-12)%M minutes (00=59)%s seconds (00-59)%a local simplified week name%A Local Full week name%b Local simplified month name%B Local Full month name%c Local corresponding date representation and time representation%j Day of the Year (001-366)%p equivalent of local a.m. or P.M.%u days of the year (00-53) Sunday for the beginning of the week%w Week (0-6), Sunday for the beginning of the week%W number of weeks in the year (00-53) Monday for the beginning of the week%x Local corresponding date representation%X Local corresponding time representation%Z name of the current time zonePercent% of the number itself

Time Formatting symbols

(3) tuple (struct_time): Struct_time A total of 9 elements total nine elements: (years, months, days, hours, minutes, seconds, the first week of the year, the day of the year, etc.

1 Import Time2 3 4 Print(Time.asctime ())#format of return time: Sun may 21:31:15 20185 Print(Time.time ())#return timestamp: 1526823135.95312056 Print(Time.gmtime ())#the same as the time.localtime () effect; Returns the struct time object format for local times: Time.struct_time (tm_year=2018, tm_mon=5, tm_mday=20, tm_hour=13, Tm_min=33, tm_sec=33, tm_wday=6, tm_yday=140, tm_isdst=0)7 Print(Time.localtime ())8 Print(Time.strftime ("%y-%m-%d"))#returns the current time in a custom format: 2018-05-209 Print(Time.strptime ("2018-05-20","%y-%m-%d"))#Convert The specified time to a struct the Date object format: Time.struct_time (tm_year=2018, tm_mon=5, tm_mday=20, tm_hour=0, tm_min=0, tm_sec=0, tm_ Wday=6, tm_yday=140, Tm_isdst=-1)

1 Importdatetime2 3 Print(Datetime.datetime.now ())#return Current time: 2018-05-20 21:42:57.4867704 Print(Datetime.date.fromtimestamp (Time.time ()))#convert timestamp to TIME format: 2018-05-205 Print(Datetime.datetime.now () + Datetime.timedelta (3))#return time on current date + 3 days6 Print(Datetime.datetime.now () + Datetime.timedelta (-3))#return time on current date-3 days7 Print(Datetime.datetime.now () + Datetime.timedelta (hours= 3))#return time at current time + 3 hours8 Print(Datetime.datetime.now () + Datetime.timedelta (minutes=30))#return time at current time + 30 minutes

Second, random module (stochastic number module):

1 ImportRandom2 3 Print(Random.random ())#returns a decimal between 0 and 1:0.92280974804305174 Print(Random.uniform (1,3))#returns any floating-point number for a specified range5 Print(Random.randint (1,5))#returns an integer from 1 to 56 Print(Random.randrange (10))#returns an integer7 Print(Random.choice ("Hello"))#returns any element in a string8 Print(Random.sample ("Hello", 3))#returns any element of a specified number as a list9 Ten #Generate random numbers One  Arandomnum="" -  forIinchRange (5): -  theAddnum=random.choice ([Random.randint (1.,10), Chr (Random.randint (65,90))]) -randomnum+=Str (addnum) -  - Print(Randomnum)

Python_ Common built-in modules