I have a DataFrame called 'df' like the following:
+-------+-------+-------+
| Atr1 | Atr2 | Atr3 |
+-------+-------+-------+
| A | A | A |
+-------+-------+-------+
| B | A | A |
+-------+-------+-------+
| C | A | A |
+-------+-------+-------+
I want to add a new column to it with incremental values and get the following updated DataFrame:
+-------+-------+-------+-------+
| Atr1 | Atr2 | Atr3 | Atr4 |
+-------+-------+-------+-------+
| A | A | A | 1 |
+-------+-------+-------+-------+
| B | A | A | 2 |
+-------+-------+-------+-------+
| C | A | A | 3 |
+-------+-------+-------+-------+
How could I get it?