[英]Adding column to list in python
我有以下清單:
Training_Frame = pca.fit_transform(np_scaled_train)
具有以下形狀(2358,4)
我想添加第五列,此列保存在pandas數據框中,為此,在此嘗試的操作沒有成功:
Training_Frame.append(dataframe_train.iloc[:,-1])
AttributeError: 'numpy.ndarray' object has no attribute 'append'
所以我嘗試了以下
saved_frame = np.append(Training_Frame,dataframe_train.iloc[:,-1])
# This works but the result has a weird shape `(11790,)` despite :
np.shape(dataframe_train.iloc[:,-1]) # is (2358,) so I'm expecting or hopping to get a shape like `(2358,5)
`
所以我有點不明白這里是什么問題,任何想法我該怎么做?
如果Training_Frame
和dataframe_train
的長度相同:
Training_Frame = np.column_stack((Training_Frame, dataframe_train.iloc[:,-1].values))
或者,您可以從NDArray生成一個DataFrame(如@ayhan在注釋中建議的那樣):
Training_Frame = pd.DataFrame(Training_Frame).assign(column_name=dataframe_train.iloc[:,-1])
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