I have a table with the names of the countries in the columns and the names of the years in the first rows, with the values: the number of population in that country in that year. How do I change this table so that the columns are Year, country and value. I learn the first table is a pivot table. Then how can i change pivot table to a dataframe?
The first table looks like this
| Year | China | India | .... | 
|---|---|---|---|
| 2021 | 1.311.750.000 | 1.274.917.850 | .... | 
| 2022 | 1.411.750.000 | 1.374.917.850 | .... | 
So a table whose content will be as follows
| year | country | value | 
|---|---|---|
| 2022 | China | 1.411.750.000 | 
| 2022 | India | 1.374.917.850 | 
| .... | ..... | .... | 
Thanks in advance for your help
