Exercise: Database Migration |2|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You are working for a fan club website, and for pricing reasons,
management told you that they have decided to change the database
service. Since you are in charge of the database, you are also in charge
of the database migration. You need to read from your old database files
and create new files that are compatible with the new database service.

The old database files are in the following format:

.. |2| image:: ../../figures/difficulty_three.png
   :class: difficulty

::

   Actor,EpisodeCount,LastOccurence
   Kenan Thompson,353,2020
   Seth Meyers,255,2018
   Fred Armisen,238,2020
   Kate McKinnon,179,2020

New database files should be in the following format:

::

   Actor:Kenan Thompson,EpisodeCount:353,LastOccurence:2020
   Actor:Seth Meyers,EpisodeCount:255,LastOccurence:2018
   Actor:Fred Armisen,EpisodeCount:238,LastOccurence:2020
   Actor:Kate McKinnon,EpisodeCount:179,LastOccurence:2020

Write a function named *format_for_migration* which takes input two
*string* values as file paths for input and output files, where the
format of the input and the output files are shown above. This function
must fill the output file with the records. The function should also
return an *integer* which is the number of records that are formatted.

*Hint:* You can use the built-in *map*\ (), *join*\ (), *rstrip*\ () and
*split*\ () functions.

.. container:: sampleio

   Sample I/O:

.. code:: default

   Sample function call:  
       format_for_migration("input.txt", "output.txt")  

   Content of the file "input.txt":  
       Actor,EpisodeCount,LastOccurence
       Kenan Thompson,353,2020
       Seth Meyers,255,2018
       Fred Armisen,238,2020
       Kate McKinnon,179,2020
       Cecily Strong,174,2020
       Bill Hader,167,2020
       Maya Rudolp,166,2020
       Will Forte,159,2016
       Tina Fey,154,2020
       Tracy Morgan,154,2019
       Amy Poehler,153,2020
       Will Ferrell,151,2019
       Rachel Dracht,150,2020
       Colin Jost,149,2020
       Kristen Wiig,145,2020
       Andy Samberg,144,2018
       Michael Che,132,2020
       Pete Davidson,132,2020
       Alec Baldwin,65,2020
       Julia Louis-Dreyfus,60,2016
       Jenny Slate,22,2010
       Steve Martin,32,2019
       Martin Short,28,2020
       Nancy Carell,22,2018
       Steve Carell,18,2018
       Tom Hanks,18,2020
       John Mulaney,14,2020

   Return value:
       27

   Content of the file "output.txt" after function call:
       Actor:Kenan Thompson,EpisodeCount:353,LastOccurence:2020
       Actor:Seth Meyers,EpisodeCount:255,LastOccurence:2018
       Actor:Fred Armisen,EpisodeCount:238,LastOccurence:2020
       Actor:Kate McKinnon,EpisodeCount:179,LastOccurence:2020
       Actor:Cecily Strong,EpisodeCount:174,LastOccurence:2020
       Actor:Bill Hader,EpisodeCount:167,LastOccurence:2020
       Actor:Maya Rudolp,EpisodeCount:166,LastOccurence:2020
       Actor:Will Forte,EpisodeCount:159,LastOccurence:2016
       Actor:Tina Fey,EpisodeCount:154,LastOccurence:2020
       Actor:Tracy Morgan,EpisodeCount:154,LastOccurence:2019
       Actor:Amy Poehler,EpisodeCount:153,LastOccurence:2020
       Actor:Will Ferrell,EpisodeCount:151,LastOccurence:2019
       Actor:Rachel Dracht,EpisodeCount:150,LastOccurence:2020
       Actor:Colin Jost,EpisodeCount:149,LastOccurence:2020
       Actor:Kristen Wiig,EpisodeCount:145,LastOccurence:2020
       Actor:Andy Samberg,EpisodeCount:144,LastOccurence:2018
       Actor:Michael Che,EpisodeCount:132,LastOccurence:2020
       Actor:Pete Davidson,EpisodeCount:132,LastOccurence:2020
       Actor:Alec Baldwin,EpisodeCount:65,LastOccurence:2020
       Actor:Julia Louis-Dreyfus,EpisodeCount:60,LastOccurence:2016
       Actor:Jenny Slate,EpisodeCount:22,LastOccurence:2010
       Actor:Steve Martin,EpisodeCount:32,LastOccurence:2019
       Actor:Martin Short,EpisodeCount:28,LastOccurence:2020
       Actor:Nancy Carell,EpisodeCount:22,LastOccurence:2018
       Actor:Steve Carell,EpisodeCount:18,LastOccurence:2018
       Actor:Tom Hanks,EpisodeCount:18,LastOccurence:2020
       Actor:John Mulaney,EpisodeCount:14,LastOccurence:2020