Python timedelta()函数存在于datetime库中，该函数通常用于计算日期差，也可以用于Python中的日期操作。这是执行日期操作的最简单方法之一。

用法： datetime.timedelta(days=0, seconds=0, microseconds=0, milliseconds=0, minutes=0, hours=0, weeks=0)

返回值：日期

代码1：

# Timedelta function demonstration

from datetime import datetime, timedelta

# Using current time

ini_time_for_now = datetime.now()

# printing initial_date

print ("initial_date", str(ini_time_for_now))

# Calculating future dates

# for two years

future_date_after_2yrs = ini_time_for_now + \

timedelta(days = 730)

future_date_after_2days = ini_time_for_now + \

timedelta(days = 2)

# printing calculated future_dates

print('future_date_after_2yrs:', str(future_date_after_2yrs))

print('future_date_after_2days:', str(future_date_after_2days))

输出：

initial_date 2019-02-27 12:41:45.018389

future_date_after_2yrs:2021-02-26 12:41:45.018389

future_date_after_2days:2019-03-01 12:41:45.018389

代码2：

# Timedelta function demonstration

from datetime import datetime, timedelta

# Using current time

ini_time_for_now = datetime.now()

# printing initial_date

print ("initial_date", str(ini_time_for_now))

# Calculating past dates

# for two years

past_date_before_2yrs = ini_time_for_now - \

timedelta(days = 730)

# for two hours

past_date_before_2hours = ini_time_for_now - \

timedelta(hours = 2)

# printing calculated past_dates

print('past_date_before_2yrs:', str(past_date_before_2yrs))

print('past_date_after_2days:', str(past_date_before_2hours))

输出：

initial_date 2019-02-27 12:41:46.104662

past_date_before_2yrs:2017-02-27 12:41:46.104662

past_date_after_2days:2019-02-27 10:41:46.104662

代码3：

# Timedelta function demonstration

from datetime import datetime, timedelta

# Using current time

ini_time_for_now = datetime.now()

# printing initial_date

print ("initial_date", str(ini_time_for_now))

# Some another datetime

new_final_time = ini_time_for_now + \

timedelta(days = 2)

# printing new final_date

print ("new_final_time", str(new_final_time))

# printing calculated past_dates

print('Time difference:', str(new_final_time - \

ini_time_for_now))

输出：

initial_date 2019-02-27 12:41:47.386595

new_final_time 2019-03-01 12:41:47.386595

Time difference:2 days, 0:00:00