I have to object against reusing the 'data' var. Make up a new name for each assignment in particular when types and data structures change (like the last step is switching from strings to ints).
Other than that I think both styles are fine.
Other than that I think both styles are fine.
Another problem of having different names for each step is that you can no longer quickly comment out a single step to try things out, which you can if you either have the pipeline or a single variable name.