python - 如何创建一个带有 2 个数据帧的 pandas 数据帧，一个作为列，一个作为行

Question

我有 2 个数据框如下:

df1 = pd.DataFrame({'Barcode':[1,2,3,4],'Store':['s1','s2','s3','s4']})    

df2 = pd.DataFrame({'Date':['2020-10-10','2020-10-09','2020-10-08','2020-10-07','2020-10-06']})

如何拥有一个数据框，其中 df1 作为行，df2 作为列，从而生成具有空值的单元格。如下所示:

最后一步是在另一个表(df4)上用连接填充单元格:

df4 = pd.DataFrame({'Barcode':[1,2,3,4],'Store':['s1','s2','s3','s4'],'2020-10-10':[1,2,5,np.nan],'2020-10-09':[np.nan,2,3,0],'2020-10-08':[0,0,2,3],'2020-10-07':[np.nan,1,np.nan,2]})

最终的 df 应该如下所示:

非常感谢任何帮助。

Answer 1

希望我正确理解了您的问题。您有 3 个数据框:

df1 = pd.DataFrame({'Barcode':[1,2,3,4],'Store':['s1','s2','s3','s4']})    
df2 = pd.DataFrame({'Date':['2020-10-10','2020-10-09','2020-10-08','2020-10-07','2020-10-06']})
df4 = pd.DataFrame({'Barcode':[1,2,3,4],'Store':['s1','s2','s3','s4'],'2020-10-10':[1,2,5,np.nan],'2020-10-09':[np.nan,2,3,0],'2020-10-08':[0,0,2,3],'2020-10-07':[np.nan,1,np.nan,2]})

---

然后:

df1 = pd.DataFrame(df1, columns= df1.columns.tolist() + df2['Date'].tolist())
df1 = df1.set_index('Barcode')
df4 = df4.set_index('Barcode')

print(df1.fillna(df4))

打印:

        Store  2020-10-10  2020-10-09  2020-10-08  2020-10-07  2020-10-06
Barcode                                                                  
1          s1         1.0         NaN         0.0         NaN         NaN
2          s2         2.0         2.0         0.0         1.0         NaN
3          s3         5.0         3.0         2.0         NaN         NaN
4          s4         NaN         0.0         3.0         2.0         NaN