我有一個包含兩列、日期和類別的 DataFrame。我想根據規則創建一個新的日期列：如果類別是B那么值應該是最接近日期的工作日（僅來自過去或當天本身），否則它是日期列本身的值。我將工作日定義為不在周末的任何一天，也不出現在holidays下面最小示例中定義的列表中。請考慮以下 DataFrame df：import datetime as dtimport pandas as pdfrom IPython.display import displayholidays = [dt.datetime(2018, 10, 11)]df = pd.DataFrame({"day": ["2018-10-10", "2018-10-11", "2018-10-12", "2018-10-13", "2018-10-14", "2018-10-15" ], "category":["A", "B", "C", "B", "C", "A"] })df["day"] = pd.to_datetime(df.day, format="%Y-%m-%d")display(df) day category0 2018-10-10 A1 2018-10-11 B2 2018-10-12 C3 2018-10-13 B4 2018-10-14 C5 2018-10-15 A如何獲得第三列，其值為下面列出的值？2018-10-102018-10-102018-10-122018-10-122018-10-142018-10-15我創建了一個函數，可以在處理列表時查找最后一個工作日，如果有幫助的話。# creates a list whose elements are all days in the years 2017, 2018 and 2019days = [dt.datetime(2017, 1 , 1) + dt.timedelta(k) for k in range(365*3)]def lastt_bus_day(date): return max( [d for d in days if d.weekday() not in [5, 6] and d not in holidays and d <= date ] )for d in df.day: print(last_bus_day(d))#prints2018-10-10 00:00:002018-10-10 00:00:002018-10-12 00:00:002018-10-12 00:00:002018-10-12 00:00:002018-10-15 00:00:00
3 回答
躍然一笑
TA貢獻1826條經驗 獲得超6個贊
Pandas 支持通過自定義工作日提供您自己的假期。
該解決方案的好處是無縫支持相鄰的假期；例如，某些地區的節禮日和圣誕節。
# define custom business days
weekmask = 'Mon Tue Wed Thu Fri'
holidays = ['2018-10-11']
bday = pd.tseries.offsets.CustomBusinessDay(holidays=holidays, weekmask=weekmask)
# construct mask to identify when days must be sutracted
m1 = df['category'] == 'B'
m2 = df['day'].dt.weekday.isin([5, 6]) | df['day'].isin(holidays)
# apply conditional logic
df['day'] = np.where(m1 & m2, df['day'] - bday, df['day'])
print(df)
category day
0 A 2018-10-10
1 B 2018-10-10
2 C 2018-10-12
3 B 2018-10-12
4 C 2018-10-14
5 A 2018-10-15
編輯：根據您的評論，“我剛剛意識到我沒有問清楚我想要什么。我想找到前一個工作日”，您可以簡單地使用：
df['day'] -= bday
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