【Python】現在時刻など時刻関連諸々

import subprocess
import time
from datetime import datetime, timedelta
from calendar import monthrange

# 時刻取得・操作サンプル
now = datetime.now()
print("今の時間:", now)

tomorrow = now + timedelta(days=1)
print("明日の同じ時間:", tomorrow)

one_hour_later = now + timedelta(hours=1)
print("1時間後:", one_hour_later)

thirty_minutes_later = now + timedelta(minutes=30)
print("30分後:", thirty_minutes_later)

ten_seconds_later = now + timedelta(seconds=10)
print("10秒後:", ten_seconds_later)

today_2359 = now.replace(hour=23, minute=59, second=0, microsecond=0)
print("今日の23:59:", today_2359)

today_0000 = now.replace(hour=0, minute=0, second=0, microsecond=0)
print("今日の00:00:", today_0000)

tomorrow_0000 = (now + timedelta(days=1)).replace(hour=0, minute=0, second=0, microsecond=0)
print("明日の00:00:", tomorrow_0000)

last_day = monthrange(now.year, now.month)[1]
month_end = now.replace(day=last_day, hour=23, minute=59, second=59, microsecond=0)
print("今月末:", month_end)

month_start = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
print("今月初:", month_start)

one_week_later = now + timedelta(weeks=1)
print("1週間後:", one_week_later)

one_week_ago = now - timedelta(weeks=1)
print("1週間前:", one_week_ago)

three_days_later_noon = (now + timedelta(days=3)).replace(hour=12, minute=0, second=0, microsecond=0)
print("3日後の12:00:", three_days_later_noon)

five_minutes_ago = now - timedelta(minutes=5)
print("5分前:", five_minutes_ago)

one_year_ago = now.replace(year=now.year - 1)
print("1年前:", one_year_ago)

one_year_later = now.replace(year=now.year + 1)
print("1年後:", one_year_later)

ten_years_later = now.replace(year=now.year + 10)
print("10年後:", ten_years_later)

def add_months(dt, months):
    month = dt.month - 1 + months
    year = dt.year + month // 12
    month = month % 12 + 1
    day = min(dt.day, monthrange(year, month)[1])
    return dt.replace(year=year, month=month, day=day)
one_month_later = add_months(now, 1)
print("1か月後:", one_month_later)

one_day_ago = now - timedelta(days=1)
print("1日前:", one_day_ago)

one_hour_ago = now - timedelta(hours=1)
print("1時間前:", one_hour_ago)

one_minute_later = now + timedelta(minutes=1)
print("1分後:", one_minute_later)

one_second_later = now + timedelta(seconds=1)
print("1秒後:", one_second_later)

one_second_ago = now - timedelta(seconds=1)
print("1秒前:", one_second_ago)

weekdays_jp = ["月", "火", "水", "木", "金", "土", "日"]
print("今日の曜日:", weekdays_jp[now.weekday()])

print("ISOフォーマット:", now.isoformat())

print("UNIXタイムスタンプ:", now.timestamp())

def get_next_target_second(now: datetime, interval: int) -> datetime:
    # 次の実行タイミング（00, 20, 40秒）
    current_second = now.second
    next_second = ((current_second // interval) + 1) * interval
    if next_second >= 60:
        # 次の分へ繰り上げ
        now = now + timedelta(minutes=1)
        next_second = 0
    return now.replace(second=next_second, microsecond=0)

def sleep_until(target_time: datetime):
    while True:
        now = datetime.now()
        remaining = (target_time - now).total_seconds()
        if remaining <= 0:
            break
        time.sleep(min(remaining, 0.1))

def run_every_20_seconds():
    interval = 20  # 実行間隔（秒）
    while True:
        now = datetime.now()
        next_exec_time = get_next_target_second(now, interval)
        sleep_until(next_exec_time)

        result = subprocess.run("echo Hello", capture_output=True, text=True, shell=True)
        print(f"[{datetime.now()}] コマンド実行: {result.stdout.strip()}")

if __name__ == "__main__":
    run_every_20_seconds()

PS> python .\main.py
今の時間: 2025-06-17 23:43:24.664432
明日の同じ時間: 2025-06-18 23:43:24.664432
1時間後: 2025-06-18 00:43:24.664432
30分後: 2025-06-18 00:13:24.664432
10秒後: 2025-06-17 23:43:34.664432
今日の23:59: 2025-06-17 23:59:00
今日の00:00: 2025-06-17 00:00:00
明日の00:00: 2025-06-18 00:00:00
今月末: 2025-06-30 23:59:59
今月初: 2025-06-01 00:00:00
1週間後: 2025-06-24 23:43:24.664432
1週間前: 2025-06-10 23:43:24.664432
3日後の12:00: 2025-06-20 12:00:00
5分前: 2025-06-17 23:38:24.664432
1年前: 2024-06-17 23:43:24.664432
1年後: 2026-06-17 23:43:24.664432
10年後: 2035-06-17 23:43:24.664432
1か月後: 2025-07-17 23:43:24.664432
1日前: 2025-06-16 23:43:24.664432
1時間前: 2025-06-17 22:43:24.664432
1分後: 2025-06-17 23:44:24.664432
1秒後: 2025-06-17 23:43:25.664432
1秒前: 2025-06-17 23:43:23.664432
今日の曜日: 火
ISOフォーマット: 2025-06-17T23:43:24.664432
UNIXタイムスタンプ: 1750171404.664432