Pandas 值从一个df转移到另一个溢出错误

Question

Is there pandas way to copy values to column 'column_to_fill' from another df without itterations? I have needed me row and column indexes in df_1 columns. I need to fill df_1['column_to_fill'] with values from df_2.

df1 = pd.DataFrame(columns=['row_df2', 'column_df2'])
df1['row_df2'] = [1, 3, 5]
df1['column_df2'] = ['a', 'c', 'd']

index=np.arange(6)
columns=['a', 'b', 'c', 'd']
df2 = pd.DataFrame(data=np.random.randint(10, size=(len(index), len(columns))), index=index, columns=columns)
df1['column_to_fill'] = 0
for idx in df1.index:
    df1.loc[idx, 'column_to_fill'] = df2.loc[df1.loc[idx, 'row_df2'], 
                                                            df1.loc[idx, 'column_df2']].sum()




    df1

  row_df2   column_df2
0   1       a
1   3       c
2   5       d

df2
        a   b   c   d
    0   2   3   5   2
    1   8   3   9   3
    2   4   6   0   1
    3   3   8   0   8
    4   3   4   5   0
    5   2   5   4   0


df1
   row_df2  column_df2  column_to_fill
0   1        a           8
1   3        c           0
2   5        d           0

Answer 1

If I understand you well, you want to assign a column from a df to another, then:

df2['column_to_fill'] = df1['col']

Answer 2

I think you want to pick the value of the df_2 based on the values(row and column combination) of df_1 and assign it to df_1 column. If that is the case then check below.,

    df_1 = pd.DataFrame({'values_type_rows_df2':[0,1,0,1], 1:[4,5,6,7]})
    df_2 = pd.DataFrame({0:['a','b','c','d'], 1:['e','a','b','c']})
    df_1['column_to_fill'] = [df_2.loc[i,i] for i in df_1['values_type_rows_df2']]