Level 4: Combining and reshaping · Exercise 49 of 63 · Pro

One row per tag with explode

A pandas exercise from Pandasdrill. Solve it with a Python editor in your browser running real pandas, and it is checked the moment you submit.

The task

Each post has its tags in one comma-separated string, such as "python,pandas". Return a DataFrame with the columns `post_id` and `tag`, one row per tag, with a fresh 0, 1, 2, ... index.

What this exercise teaches

explode makes one row per element of a list-valued column and repeats the other columns alongside. The new rows keep the original row label, so a post with three tags yields three rows labeled 2; reset_index(drop=True) gives them fresh positions. Without the split there is nothing to explode, and without explode you get lists in the cells.

A hint if you get stuck

First turn the string into a list with str.split, then call explode on that column, then reset the index.