Column names are all the same You are trying to find the product of two files with different index names. And I want to use the index name of the multiplied value as the index name of df1.

```
df3 = df1.mul(df2, fill_value=1)
```

Since I'm writing it like this Two indexes were combined into a join expression.

The calculation was done through the command prod Shows output without index name.

I want to multiply the values of the two data frames and output the result of the multiplied values. I want the index name of the result value to be the index name in df1.

If anyone knows, please answer.

pandas dataframe

2022-09-20 10:47

```
>>> df1 = pd.DataFrame({"a":[1,2,3], "b":[4,5,10]}, index=[0,1,2])
>>> df1
a b
0 1 4
1 2 5
2 3 10
>>> df2 = pd.DataFrame({"a":[11,12,13], "b":[14,15,10]}, index=[0,3,4])
>>> df2
a b
0 11 14
3 12 15
4 13 10
```

If you simply try to multiply data frames, you calculate them by matching the index.

```
>>> df1*df2
a b
0 11.0 56.0
1 NaN NaN
2 NaN NaN
3 NaN NaN
4 NaN NaN
```

```
>>> df1.values
array([[ 1, 4],
[ 2, 5],
[ 3, 10]], dtype=int64)
```

The values of the data frame are a numpy array of data frame contents. Pure array with no indexes.

```
>>> df1.values * df2.values
array([[ 11, 56],
[ 24, 75],
[ 39, 100]], dtype=int64)
>>> df1 * df2.values
a b
0 11 56
1 24 75
2 39 100
>>> df3 = df1*df2.values
>>> df3
a b
0 11 56
1 24 75
2 39 100
>>>
```

df1 can be multiplied by a numpy array of the same shape.

2022-09-20 10:47

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