[Python] Keep Returning a list from a python function iteratively back to the function

I have a simple pipe delimited file with 2 columns with plain text columns - job & dependent jobs. Data looks like this-

jobA|job1,job2,job3
jobB|job4,job5
job1|jobX,jobY
job2|Null
job3|Null
job4|jobP,jobQ
job5|Null
jobP|jobR
jobQ|Null
jobR|Null
jobX|Null
jobY|jobZ
jobZ|Null


This data talks about a particular job and all of its dependent jobs. Null means that job doesn't have any dependency (which is acceptable). All jobs are accounted for here in this table. The way to read this data is that JobA has 3 predecessor jobs- job1, job2 and job3. Job1 in turn has 2 predecessors- jobX and jobY and so on.

The requirement is to have a simple python function which takes a list of job names as input argument and drills down on all its dependent jobs (and their dependent jobs individually up to lowest level.

So if i pass ['jobA'] to this function, I should get below list in return-

['job1','job2','job3','jobX','jobY','jobZ']



If i pass ['jobB'], i should get below in return-

['job4','job5','jobP','jobQ','jobR']


If i pass the list to this function - ['jobA','jobB'] , we should get combined list.

['job1','job2','job3','jobX','jobY','jobZ','job4','job5','jobP','jobQ','jobR']

Continue reading...