残プロ 第-8回 ~pythonで第N曜日を計算する~

このプログラムではこんなことします

• datetimeモジュール，calendarモジュールを使用
• 第N曜日を文字列で受け取り，日にちに変換
• 既に過ぎていた場合は，翌月第N何曜日を計算

サンプル.py

元の文字列は"EveryDay"や"FirstMonday,EverySunday"などです．これを第-7回の関数separateStrで分割し入力しています．

sample.py

import datetime
import calendar

def str2date(str_list):
    date_list = []
    for s in str_list:
        frequency = s[0]
        weekday = s[1]
        delta = weekday_list.index(weekday) - today.weekday()
        if frequency == "Every":
            if weekday == "Day":
                date = today
            else:
                if delta < 0:
                    delta += 7
                date = today + datetime.timedelta(days=delta)
        else:
            nth = frequency_list.index(frequency) + 1
            weekday_first, _ = calendar.monthrange(year=today.year, month=today.month)
            day = 7 * (nth-1) + (weekday_list.index(weekday) - weekday_first) % 7 + 1
            if day >= today.day:
               delta = day - today.day
               date = today + datetime.timedelta(days=delta)
            else:
                weekday_first, _ = calendar.monthrange(year=today.year, month=today.month+1)
                day = 7 * (nth-1) + (weekday_list.index(weekday) - weekday_first) % 7 + 1
                date = datetime.date(year=today.year, month=today.month+1, day=1) + datetime.timedelta(days=day-1)
        date_list.append(date)
    return date_list


frequency_list = ['First', 'Second', 'Third', 'Fourth']
weekday_list = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
today = datetime.date.today()

第N曜日の計算にはnkmkさんのサイトを参考にさせていただきました．