I pre-processing the data i have dataframe like
id ref text
+------+------+--------------------+
| 8309| 3129|3 MO F/U HAIR LOS...|
| 8309| 3129| 4 MO SKIN CK|
| 8309| 3129| 4 MO F/U LM AG|
| 8309| 3129|HAIR LOSS AND SPO...|
| 8309| 3129| 2 MO F/U CONF KC|
| 8309| 3129|SSR AND DISCUSS H...|
| 4569| 1101|F/U LM TO CONFIRM...|
| 4569| 1101|F/U (LF) LM TO CO...|
| 4569| 1101| FU CONFIRMED|
| 4569| 1101|F/U MRI RESULTS ...|
| 4569| 1101|F/U AFTER MRI JC ...|
| 4569| 1101| FU|
| 4569| 1101|F/U AND NEW PROBL...|
| 4569| 1101| F/U|
| 4569| 1101| FU CONFIRMED|
| 4569| 1101|REVIEW MRI ...|
| 4569| 1101|REVIEW MRI RESULT...|
+------+------+--------------------+
I want to convert this Dataframe like this
id ref text
+--------+------+--------------------+
| 8309 | 3129|3 MO F/U HAIR LOS...|
| 8309_1| 3129| 4 MO SKIN CK|
| 8309_2| 3129| 4 MO F/U LM AG|
| 8309_3| 3129|HAIR LOSS AND SPO...|
| 8309_4| 3129| 2 MO F/U CONF KC|
| 8309_5| 3129|SSR AND DISCUSS H...|
| 4569 | 1101|F/U LM TO CONFIRM...|
| 4569_1| 1101|F/U (LF) LM TO CO...|
| 4569_2| 1101| FU CONFIRMED|
| 4569_3| 1101|F/U MRI RESULTS ...|
|--------|------|--------------------|
i want just bind the repeated ID with unique number. If it not incremental it will be fine.