python - 当两个数据框的列名匹配时查找值

我想编写一个函数，当df1和df2的列名彼此匹配时更新df1的值。

例如：
df1：

    Name | Graduated | Employed | Married
    AAA       1           2         3
    BBB       0           1         2
    CCC       1           0         1

df2：

    Answer_Code | Graduated | Employed | Married
       0                No         No        No
       1                Yes       Intern    Engaged
       2                N/A        PT        Yes
       3                N/A        FT      Divorced

最后结果：
df3：

     Name | Graduated |   Employed   |  Married
     AAA       Yes          PT         Divorced
     BBB       No           Intern     Yes
     CCC       Yes          No         NO

我想编写如下代码：

     IF d1.columns = d2.columns THEN

     df1.column.update(df1.column.map(df2.set_index('Answer_Code').column))

最佳答案

一种方法是利用pd.DataFrame.lookup：

df1 = pd.DataFrame({'Name': ['AAA', 'BBB', 'CCC'],
                    'Graduated': [1, 0, 1],
                    'Employed': [2, 1, 0],
                    'Married': [3, 2, 1]})

df2 = pd.DataFrame({'Answer_Code': [0, 1, 2, 3],
                    'Graduated': ['No', 'Yes', np.nan, np.nan],
                    'Employed': ['No', 'Intern', 'PT', 'FT'],
                    'Married': ['No', 'Engaged', 'Yes', 'Divorced']})

# perform lookup on df2 using row & column labels from df1
arr = df2.set_index('Answer_Code')\
         .lookup(df1.iloc[:, 1:].values.flatten(),
                 df1.columns[1:].tolist()*3)\
         .reshape(3, -1)

# copy df1 and allocate values from arr
df3 = df1.copy()
df3.iloc[:, 1:] = arr

print(df3)

  Name Graduated Employed    Married
0  AAA       Yes       PT   Divorced
1  BBB        No   Intern        Yes
2  CCC       Yes       No    Engaged

关于python - 当两个数据框的列名匹配时查找值，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/50787213/