Python - 将日期数字转换为特定年份的日期

给定天数，转换为它所指的日期。

Input : day_num = “339”, year = “2020” 
Output : 12-04-2020 
Explanation : 339th Day of 2020 is 4th December.

Input : day_num = “4”, year = “2020” 
Output : 01-04-2020 
Explanation : 4th Day of 2020 is 4th January. 

方法 #1：使用 datetime.strptime()

在此，我们获取年份字符串和日期数字字符串，并传递给 strptime()，转换为相应的所需日期。

Python3

# Python3 code to demonstrate working of
# Convert day number to date in particular year
# Using datetime.strptime()
from datetime import datetime
  
# initializing day number
day_num = "339"
  
# print day number
print("The day number : " + str(day_num))
  
# adjusting day num
day_num.rjust(3 + len(day_num), '0')
  
# Initialize year
year = "2020"
  
# converting to date
res = datetime.strptime(year + "-" + day_num, "%Y-%j").strftime("%m-%d-%Y")
  
# printing result
print("Resolved date : " + str(res))

输出

The day number : 339
Resolved date : 12-04-2020

方法#2：使用timedelta()

在这里，我们将日期初始化为 1 月 1 日，然后使用 timedelta() 添加天数，结果给出了所需的日期。

蟒蛇3

# Python3 code to demonstrate working of
# Convert day number to date in particular year
# Using datetime.strptime()
from datetime import datetime, date, timedelta
  
# initializing day number
day_num = "339"
  
# print day number
print("The day number : " + str(day_num))
  
# adjusting day num
day_num.rjust(3 + len(day_num), '0')
  
# Initialize year
year = "2020"
  
# Initializing start date
strt_date = date(int(year), 1, 1)
  
# converting to date
res_date = strt_date + timedelta(days=int(day_num) - 1)
res = res_date.strftime("%m-%d-%Y")
  
# printing result
print("Resolved date : " + str(res))

输出

The day number : 339
Resolved date : 12-04-2020