计算时间差，单位为hh:mm

import datetime

def calculate_time_difference(start_time, end_time):
    # 将时间字符串转换为日期时间对象
    start_datetime = datetime.datetime.strptime(start_time, "%H:%M")
    end_datetime = datetime.datetime.strptime(end_time, "%H:%M")

    # 计算时间差
    time_difference = end_datetime - start_datetime

    # 提取小时数和分钟数
    hours = time_difference.seconds // 3600
    minutes = (time_difference.seconds // 60) % 60

    # 格式化为hh:mm的形式
    time_difference_formatted = "{:02d}:{:02d}".format(hours, minutes)

    return time_difference_formatted

# 示例用法
start_time = "09:30"
end_time = "13:45"
time_difference = calculate_time_difference(start_time, end_time)
print("时间差为：", time_difference)