The introduction of the processing time and the method of realizing timing task in Python3 _python

Regardless of the programming language, time is certainly a very important part of today to see how Python handles time and Python timed tasks, note: This is the Python3 version of the implementation, in the Python2 version of the implementation of a slightly different, there will be time to write another article to distinguish.
1. Calculate the date of tomorrow and yesterday

#! /usr/bin/env python
#coding =utf-8
# Get today, Yesterday and Tomorrow
# introduce a datetime module
import datetime 
#计算今天的时间
Today = Datetime.date.today ()
#计算昨天的时间 
yesterday = Today-datetime.timedelta (days = 1)
#计算明天的时间
Tomorrow = Today + Datetime.timedelta (days = 1) 
#打印这三个时间
print (Yesterday, today, tomorrow)

2. Calculate the previous time

Method One:

#! /usr/bin/env python
#coding =utf-8
# Calculates the previous time
#引入datetime, calendar two modules
import datetime, Calendar
 
last_friday = Datetime.date.today () 
oneday = Datetime.timedelta (days = 1) while 
 
Last_ Friday.weekday ()!= calendar. FRIDAY: 
 Last_friday-= oneday 
 
print (Last_friday.strftime ('%A,%d-%b-%y ')

Method Two: Look for the last Friday with the help of modulo arithmetic

#! /usr/bin/env python
#coding =utf-8
# with modulo, you can work out the number of days you need to subtract, calculate the last Friday
#同样引入datetime, calendar two modules
Import datetime 
Import calendar 
 
today = Datetime.date.today () 
target_day = Calendar. FRIDAY 
this_day = Today.weekday () 
delta_to_target = (this_day-target_day)% 7
last_friday = Today-dateti Me.timedelta (days = delta_to_target) 
 
print (Last_friday.strftime ("%d-%b-%y"))

3. Calculate the total playback time of a song

#! /usr/bin/env python
#coding =utf-8
# Gets the play time of all songs in a list and 
import datetime 
 
def Total_timer (Times): 
 td = Datetime.timedelta (0) 
 duration = SUM ([Datetime.timedelta (minutes = m, seconds = s) for M, s in times], TD) 
   return duration 
 
times1 = [(2), 
   (3, (3), 
   ] 
times2 = [(3, 0), 
   (5 
   ), (4 , 
   (1), 
   ] 
 
assert Total_timer (times1) = = Datetime.timedelta (0, 596) 
assert Total_timer ( Times2 = = Datetime.timedelta (0, 815) 
 
print ("Tests passed.\n"
  "total:%s\n" "
  Second Test Total:%s% (Total_timer (times1), Total_timer (Times2)))

4. Repeatedly executing a command

#! /usr/bin/env python
#coding =utf-8
# Executes a command import time at the required interval 
 
, OS 
 
def re_exe (cmd, inc = 60): While 
 True: 
  os.system (cmd); 
  Time.sleep (inc) 
 
Re_exe ("Echo%time%", 5)

5. Timed Tasks

#! /usr/bin/env python
#coding =utf-8
#这里需要引入三个模块
import time, OS, Sched 
 
# The first parameter determines the duration of the task. Returns the number of seconds from a specific time to the current experience 
# The second parameter measures time in some artificial way 
schedule = Sched.scheduler (Time.time, Time.sleep) 
 
def perform_ Command (CMD, Inc): 
 Os.system (cmd) 
  
def timming_exe (cmd, inc =): 
 # Enter to schedule the occurrence of an event, starting from now n seconds 
 Schedule.enter (inc, 0, Perform_command, (CMD, Inc)) 
 # continues to run until the scheduled time queue becomes empty 
 schedule.run () 
  
 
print ("Show After seconds: " 
timming_exe (" Echo%time% ", 10)

6. Using Sched to implement cycle calls

#! /usr/bin/env python
#coding =utf-8
import time, OS, Sched 
 
# The first parameter determines the duration of the task, and returns the number of seconds from a specific time to the current experience. 
The second parameter measures time in some artificial way 
schedule = Sched.scheduler (Time.time, Time.sleep) 
 
def Perform_command (CMD, Inc.): 
 # Schedule it to run itself again after Inc, which is the cycle run 
 Schedule.enter (inc, 0, Perform_command, (CMD, Inc) 
 Os.system (cmd) 
  
def timming_exe (cmd, inc =): 
 # Enter to schedule the occurrence of an event, starting from now n seconds to start 
 Schedule.enter (inc, 0, Perform_command, (CMD, Inc)) 
 # Run continuously until the scheduled time queue becomes empty 
 schedule.run () 
  
 
print ("Show Seconds:") 
Timming_exe ("Echo%time%", 10)