[Arrangement] conversion and calculation of strings and time in Python

1. conversions between string time and datetime 1. String-> time>>> Time. strptime ('2017-08-04 ',' % Y-% m-% D ')
Time. struct_time (tm_year = 2012, tm_mon = 8, tm_mday = 4, tm_hour = 0, tm_min = 0, tm_sec = 0, tm_wday = 5, tm_yday = 217, tm_isdst =-1) 2. Time-> string>>> Import time # method 1
>>> Time. strftime ('% Y-% m-% d', time. localtime () #'2017-08-04' # method 2
>>> Time. strftime ('% Y-% m-% d', time. localtime (time. time () #'2017-08-04 'Where strftime (which should be the meaning of string format time) is used to format the time. The first parameter is the formatted string, the second parameter is a struct, and time. the time () function is used to obtain the machine time. 3. String-> datetime# Method 1 convert data by string-> time-> datetime> Import datetime
>>> Datetime. datetime ( *Time. strptime ('2017-08-04 ',' % Y-% m-% D') [: 3]) # datetime. datetime (2012, 8, 4, 0, 0) # method 2 >>> import datetime >>> datetime. datetime. strptime ('2017-08-04 ',' % Y-% m-% D') # datetime. datetime (2012, 8, 4, 0, 0) 4. datetime-> string>>> Import datetime >>> now = time. localtime () >>> dt = datetime. datetime (* now [: 3]) # returns a string in the specified format >>> DT. strftime (format = '% Y-% m-% D') #'2017-08-04' # returns a string in the default format >>> DT. ctime () # 'sat Aug 4 00:00:00 123' 5. Time-> datetime>>> Import datetime
>>> Now = time. localtime () >>> datetime. datetime (* now [: 3]) # datetime. datetime (2012, 8, 4, 0, 0) 6. datetime-> time>>> DT. timetuple ()
Output: time. struct_time (tm_year = 2012, tm_mon = 8, tm_mday = 4, tm_hour = 0, tm_min = 0, tm_sec = 0, tm_wday = 5, tm_yday = 217, tm_isdst =-1) Ii. datetime CalculationAddition and subtraction of datetime will involve timedelta 1. time subtraction>>> Dt1 = datetime. datetime (2012, 8, 4, 20, 33, 34)
>>> Dt2 = datetime. datetime (2012, 7, 5, 14, 22, 32)
>>> Dt1-dt2 # datetime. timedelta (30,222 62) >>> (dt1-dt2). Days #30 2. After a period of time or before>>> Dt1 + datetime. timedelta (days = 10) # datetime. datetime (2012, 8, 14, 20, 33, 34)> dt1-datetime.timedelta (days = 10) # datetime. datetime (2012, 7, 25, 20, 33, 34) >>> dt4 = datetime. date (2012, 8, 14)
>>> Dt5 = datetime. Date (2012, 7, 22)
>>> Dt4-dt5 # datetime. timedelta (23)