python获取时间串的方法

from datetime import timedelta, date, datetime
                                              
def get_day_of_day(n=7):                   
    return date.today() - timedelta(days=n)
#today                                     
date=get_day_of_day(0)
print date            
                      
#yesterday            
date=get_day_of_day(1)
print date               
                                    
#before 7 days                                          
date_list=[]                                            
for index in range(0, 7):                               
    six_date = get_day_of_day(index)                    
    str_six_date = datetime.strftime(six_date, '%Y%m%d')
    date_list.append(str_six_date)                      
print date_list                   
                         
#逆序
date_list=date_list[::-1]                      
print date_list                                
                                               
#指定格式时间串             
date=datetime.now().strftime('%Y%m%d %H:%M:%S')
print date                                                                      
                                                                                
#before 1 hour 时间戳                                                                  
import time                                                                     
start_time = (datetime.now() - timedelta(hours=1)).strftime("%Y-%m-%d %H:%M:%S")
start = int(time.mktime(time.strptime(start_time, '%Y-%m-%d %H:%M:%S')))          
print start                                                                       
                                                                                  
#before 5 minutes  时间戳                                                               
start_time = (datetime.now() - timedelta(minutes=5)).strftime("%Y-%m-%d %H:%M:%S")