如何用time模块替代datetime实现脚本定时启动并支持输入启动时间？

Got it, let's work through this problem based on your needs. Since you only care about hours, minutes, and seconds (not the date), we can build a clean solution using just the time module and user input for the target start time. Below are two common scenarios you might need:

场景1：仅等待当天的目标时间（若已过则提示） #

This works if you're sure the target time hasn't passed yet today. The logic breaks down like this:

• Get the user's input in HH:MM:SS format
• Parse the input into hours, minutes, seconds
• Calculate the difference between the target time and current time (in seconds)
• Wait if the target is in the future, or throw an error if it's already passed

Here's the code:

import time

def calculate_wait_time(target_time_str):
    # Split input into hours, minutes, seconds and convert to integers
    target_hour, target_min, target_sec = map(int, target_time_str.split(':'))
    # Get current local time's hour, minute, second
    now = time.localtime()
    current_hour, current_min, current_sec = now.tm_hour, now.tm_min, now.tm_sec
    
    # Convert both times to total seconds since midnight
    target_total_sec = target_hour * 3600 + target_min * 60 + target_sec
    current_total_sec = current_hour * 3600 + current_min * 60 + current_sec
    
    # Calculate the time difference in seconds
    return target_total_sec - current_total_sec

# Get user input
target_time = input("Start time? (Use format: HH:MM:SS) ")
wait_seconds = calculate_wait_time(target_time)

if wait_seconds > 0:
    print(f"Waiting {wait_seconds} seconds until {target_time}...")
    time.sleep(wait_seconds)
    print("Time's up! Starting your script now.")
else:
    print(f"Oops, the target time {target_time} has already passed today.")

场景2：自动等待到下一次目标时间（含次日） #

If you want the script to wait until the next occurrence of the target time (even if it's tomorrow), we just adjust the time difference calculation to add a full day's seconds if the target has already passed:

import time

def calculate_next_wait_time(target_time_str):
    target_hour, target_min, target_sec = map(int, target_time_str.split(':'))
    now = time.localtime()
    current_hour, current_min, current_sec = now.tm_hour, now.tm_min, now.tm_sec
    
    target_total_sec = target_hour * 3600 + target_min * 60 + target_sec
    current_total_sec = current_hour * 3600 + current_min * 60 + current_sec
    
    wait_seconds = target_total_sec - current_total_sec
    # If target time is already past today, add 24 hours (86400 seconds) to wait until tomorrow
    if wait_seconds < 0:
        wait_seconds += 24 * 3600
    return wait_seconds

target_time = input("Start time? (Use format: HH:MM:SS) ")
wait_seconds = calculate_next_wait_time(target_time)

print(f"Waiting {wait_seconds} seconds until the next {target_time}...")
time.sleep(wait_seconds)
print("Time's up! Starting your script now.")

Quick Notes #

• Make sure users input the time in HH:MM:SS (e.g., 00:07:00 for 7 minutes past midnight). You can add input validation with try-except blocks if you want to handle invalid inputs gracefully.
• time.localtime() uses your local time zone. If you need UTC time instead, replace it with time.gmtime().

内容的提问来源于stack exchange，提问作者Julian