我有一个带有DateTimeIndex的DataFrame，我该如何将带有Index日历周的附加列添加到DataFrame。 我当前的方法是以下代码，它可以按预期工作：
output_df['week_number'] = output_df.index.week
但是我收到以下警告：
SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
我已经尝试通过更改为
来修复它output_df['week_number'] = output_df.index.week.copy()
但它没有任何改变。
进一步遵循建议并更改为.loc-accessor：
output_df.loc[:,'week_number'] = output_df.index.week
导致另一个警告：
SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-
docs/stable/indexing.html#indexing-view-versus-copy
self.obj[key] = _infer_fill_value(value)
SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-
docs/stable/indexing.html#indexing-view-versus-copy
self.obj[item] = s
避免此警告的正确方法是什么？谢谢您的帮助。