python - 你好，我正在尝试添加周开始列

Question

在我当前的表中，我有日期列，从该列我可以找到工作日。通过使用 to_timedelta 我创建了 week_start 列，但它没有给出正确的日期。代码如下:

final_data['weekday'] = final_data['DateOfInvoice'].dt.weekday

final_data['Weekstart'] = final_data['DateOfInvoice'] - pd.to_timedelta(final_data['weekday'],unit='ns', box=True, coerce=True)

输出如下:

 Date       weekday   weekstart
2016-07-23  5         2016-07-22

Answer 1

IIUC 您可以构造一个 TimedeltaIndex 并从另一列中减去:

In [152]:
df['weekstart'] = df['Date'] - pd.TimedeltaIndex(df['weekday'], unit='D')
df

Out[152]:
        Date  weekday  weekstart
0 2016-07-23        5 2016-07-18

事实上工作日列是不必要的:

In [153]:
df['weekstart'] = df['Date'] - pd.TimedeltaIndex(df['Date'].dt.dayofweek, unit='D')
df

Out[153]:
        Date  weekday  weekstart
0 2016-07-23        5 2016-07-18