So my df has some information by store ,type of product (price) , and date
the problem is that the tree different products are in columns but I need in rows.
For example my df looks like this:
| Store | PRODUCT X | PRODUCT Y | product z | date | 
|---|---|---|---|---|
| aaa | $$$$ | $$$$ | . $$$$ | 2021/02/07 | 
| bbb | $$$$ | $$$$ | . $$$$ | . | 
and I want to look like
| Store | PRODUCTS | PRICE. | date | 
|---|---|---|---|
| aaa | PRODUCT X | $$$$ | 2021/02/07 | 
| aaa | PRODUCT y | $$$$ | 2021/02/07 | 
| aaa | PRODUCT z | $$$$ | 2021/02/07 | 
| bbb | PRODUCT X | $$$$ | 2021/02/07 | 
| bbb | PRODUCT y | $$$$ | 2021/02/07 | 
| bbb | PRODUCT z | $$$$ | 2021/02/07 | 
