I have a pandas dataframe with many different elements, and I want to group similar ones and add another column representing the frequency of them. For example:
+-------+------+
| Atr1 | Atr2 |
+-------+------+
| 1 | A |
+-------+------+
| 2 | B |
+-------+------+
| 1 | A |
+-------+------+
| 3 | C |
+-------+------+
I want to get:
+-------+-------+-------+
| Atr1 | Atr2 | COUNT |
+-------+-------+-------+
| 1 | A | 2 |
+-------+-------+-------+
| 2 | B | 1 |
+-------+-------+-------+
| 3 | C | 1 |
+-------+-------+-------+
How can I do it?
