以Python方式提取星期几

Question

我有一个包含年，月，日字段的df，格式为整数。我使用以下内容提取星期几。

我该如何更精巧地做到这一点？

### First Attempt - Succeeds
lst = []
for i in zip(df['day'], df['month'], df['year']):
    lst.append(calendar.weekday(i[2], i[1], i[0]))
df['weekday'] = lst

### Second Attempt -- Fails
df['weekday'] = df.apply(lambda x: calendar.weekday(x.year, x.month, x.day))

AttributeError: ("'Series' object has no attribute 'year'", 'occurred at index cons_conf')

Answer 1

尝试使用.to_datetime和dt访问器：

import pandas as pd

data = pd.DataFrame({'year': [2018, 2018, 2018], 'month': [12, 12, 12], 'day': [1, 2, 3]})

data['weekday'] = pd.to_datetime(data[['year', 'month', 'day']]).dt.weekday

print(data)

给予：

   year  month  day  weekday
0  2018     12    1        5
1  2018     12    2        6
2  2018     12    3        0

请注意，工作日的索引为零。