python - Pandas 将字典连接到数据框

Question

我有一个现有的数据框，我正在尝试连接一个字典，其中字典的长度与数据框不同

         A        B        C
0  0.46324  0.32425  0.42194
1  0.10596  0.35910  0.21004
2  0.69209  0.12951  0.50186
3  0.04901  0.31203  0.11035
4  0.43104  0.62413  0.20567
5  0.43412  0.13720  0.11052
6  0.14512  0.10532  0.05310

和

test = {"One": [0.23413, 0.19235, 0.51221], "Two": [0.01293, 0.12235, 0.63291]}

我正在尝试将 test 添加到 df，同时将键更改为 "D" 和 "C" 我看过 https://pandas.pydata.org/pandas-docs/stable/user_guide/merging.html和 https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.concat.html这表明我应该能够将字典连接到数据框

我试过:

pd.concat([df, test], axis=1, ignore_index=True, keys=["D", "E"])
pd.concat([df, test], axis=1, ignore_index=True)

但我没有任何运气，我想要达到的结果是

         A        B        C        D        E
0  0.46324  0.32425  0.42194  0.23413  0.01293  
1  0.10596  0.35910  0.21004  0.19235  0.12235
2  0.69209  0.12951  0.50186  0.51221  0.63291
3  0.04901  0.31203  0.11035      NaN      NaN
4  0.43104  0.62413  0.20567      NaN      NaN 
5  0.43412  0.13720  0.11052      NaN      NaN
6  0.14512  0.10532  0.05310      NaN      NaN

Answer 1

假设您要将它们添加为行:

>>> pd.concat([df, pd.DataFrame(test.values(), columns=df.columns)], ignore_index=True)
         A        B        C
0  0.46324  0.32425  0.42194
1  0.10596  0.35910  0.21004
2  0.69209  0.12951  0.50186
3  0.04901  0.31203  0.11035
4  0.43104  0.62413  0.20567
5  0.43412  0.13720  0.11052
6  0.14512  0.10532  0.05310
7  0.01293  0.12235  0.63291
8  0.23413  0.19235  0.51221

如果添加为新列:

df_new = pd.concat([df, pd.DataFrame(test.values()).T], ignore_index=True, axis=1)
df_new.columns = \
    df.columns.tolist() + [{'One': 'D', 'Two': 'E'}.get(k) for k in test.keys()]

>>> df_new
         A        B        C        E        D
0  0.46324  0.32425  0.42194  0.01293  0.23413
1  0.10596  0.35910  0.21004  0.12235  0.19235
2  0.69209  0.12951  0.50186  0.63291  0.51221
3  0.04901  0.31203  0.11035      NaN      NaN
4  0.43104  0.62413  0.20567      NaN      NaN
5  0.43412  0.13720  0.11052      NaN      NaN
6  0.14512  0.10532  0.05310      NaN      NaN

字典中不能保证顺序(例如 test)，因此新的列名实际上需要映射到键。