Detailed explanation of python time processing

1. Two ways to get the current time:

import datetime,time
now = time.strftime("%Y-%m-%d %H:%M:%S")
print now
now = datetime.datetime.now()
print now

2. Get the date of the last day of the last month (the first day of this month minus 1 day)

last = datetime.date(datetime.date.today().year,datetime.date.today().month,1)-datetime.timedelta(1)
print last

3. Get the time difference (the time difference unit is seconds, commonly used (Used to calculate the time when the program is running)

starttime = datetime.datetime.now()
#long running
endtime = datetime.datetime.now()
print (endtime - starttime).seconds

4. Calculate the time 10 hours backward from the current time

d1 = datetime.datetime.now()
d3 = d1 + datetime.timedelta(hours=10)
d3.ctime()

The two commonly used classes are: datetime and timedelta. They can be added or subtracted from each other. Each class has some methods and attributes to view specific values. For example, datetime can view: days (day), hours (hour), day of the week (weekday()), etc.; timedelta can view: days (days), seconds Number (seconds) etc.

5. Time and date formatting symbols in python:

%y two-digit year representation (00-99)

%Y four-digit year representation (000-9999)

%m month (01- 12)

%d Day in the month (0-31)

%H 24-hour hour (0-23)

%I 12-hour hour (01-12)

%M Minutes (00=59)

%S Seconds (00-59)

%a Local simplified week name

%A Local complete week name

%b Local simplified month name

%B Local complete Month name

%c Local corresponding date representation and time representation

%j Day in the year (001-366)

%p Local equivalent of A.M. or P.M.

%U Number of weeks in the year (00 -53) Sunday is the beginning of the week

%w week (0-6), Sunday is the beginning of the week

%W The number of weeks in the year (00-53) Monday is the beginning of the week

%x local The corresponding date representation

%X The corresponding local time representation

%Z The name of the current time zone

%% The % number itself

Attached is the sample code:

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import datetime, calendar

def getYesterday():   
    today=datetime.date.today()   
    oneday=datetime.timedelta(days=1)   
    yesterday=today-oneday   
   return yesterday

def getToday():   
    return datetime.date.today()

#Get the dates of the previous few days for the given parameters and return a list

def getDaysByNum(num):   
     today=datetime.date.today()   
     oneday=datetime.timedelta(days=1)       
     li=[]        
    for i in range(0,num):   
        #今天减一天，一天一天减   
         today=today-oneday   
        #把日期转换成字符串   
        #result=datetostr(today)   
         li.append(datetostr(today))   
    return li   
  
#将字符串转换成datetime类型   
def strtodatetime(datestr,format):       
    return datetime.datetime.strptime(datestr,format)   
  
#时间转换成字符串,格式为2008-08-02   
def datetostr(date):     
    return    str(date)[0:10]   
  
#两个日期相隔多少天，例：2008-10-03和2008-10-01是相隔两天   
def datediff(beginDate,endDate):   
     format="%Y-%m-%d";   
     bd=strtodatetime(beginDate,format)   
     ed=strtodatetime(endDate,format)       
     oneday=datetime.timedelta(days=1)   
     count=0  
    while bd!=ed:   
         ed=ed-oneday   
         count+=1  
    return count   
  
#获取两个时间段的所有时间,返回list   
def getDays(beginDate,endDate):   
     format="%Y-%m-%d";   
     bd=strtodatetime(beginDate,format)   
     ed=strtodatetime(endDate,format)   
     oneday=datetime.timedelta(days=1)   
     num=datediff(beginDate,endDate)+1   
     li=[]   
    for i in range(0,num):   
         li.append(datetostr(ed))   
         ed=ed-oneday   
    return li   
  
#获取当前年份 是一个字符串   
def getYear():   
    return str(datetime.date.today())[0:4]   
  
#获取当前月份 是一个字符串   
def getMonth():   
    return str(datetime.date.today())[5:7]   
  
#获取当前天 是一个字符串   
def getDay():   
    return str(datetime.date.today())[8:10]      
def getNow():   
    return datetime.datetime.now()   
  
print getToday()   
print getYesterday()   
print getDaysByNum(3)   
print getDays('2008-10-01','2008-10-05')   
print '2008-10-04 00:00:00'[0:10]   
  
print str(getYear())+getMonth()+getDay()   
print getNow()