Find intersection of two nested lists?

Question

I know how to get an intersection of two flat lists:

b1 = [1,2,3,4,5,9,11,15]
b2 = [4,5,6,7,8]
b3 = [val for val in b1 if val in b2]

or

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Answer 1

flat list can be made through reduce easily.

All you need to use initializer - third argument in the reduce function.

reduce(
   lambda result, _list: result.append(
       list(set(_list)&set(c1)) 
     ) or result, 
   c2, 
   [])

Above code works for both python2 and python3, but you need to import reduce module as from functools import reduce. Refer below link for details.

• for python2

• for python3