1、reshape(1,-1)将array转化成1行： 2、reshape(-1,1)将array转化成1列： 3、shape函数:
// An highlighted block train_data.loc[train_data['Promotion'] == 'Yes',:].shape 结果：(42364, 10) train_data.loc[train_data['Promotion'] == 'Yes',:].shape[0] 结果：42364 train_data.loc[train_data['Promotion'] == 'Yes',:].shape[1] 结果：10 type(train_data.loc[train_data['Promotion'] == 'Yes',:].shape) 结果：tuple type(train_data.loc[train_data['Promotion'] == 'Yes',:]) 结果：pandas.core.frame.DataFrame