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pythonmergenested-lists
Rishav Sharan
Rishav Sharan

Reputation: 2932

Python: merge nested lists

beginner to python here.

I have 2 nested lists that I want to merge:

list1 = ['a',
         (b, c),
         (d, e),
         (f, g, h) ]

list2 = [(p,q),
         (r, s),
         (t),
         (u, v, w) ]

the output I am looking for is:

list3 = [(a, p, q),
         (b, c, r, s),
         (d, e, t),
         (f, g, h, u, v, w) ]

Can this be done without any external libraries? note: len(list1) = len(list2)

Upvotes: 8

Views: 12628

Answers (4)

Shah Vipul
Shah Vipul

Reputation: 747

Easy One

list_3 = []
list_3.extend(list_1 + list_2)

Upvotes: 0

Abdul Muneer
Abdul Muneer

Reputation: 973

If the order within an inner list/tuple is not important, you can use the mathematical set operations.

print [tuple(set(a)|set(b)) for a,b in zip(x,y)]

The set(a)|set(b) converts the iterables a and b to sets and takes the union of the two sets. They are then converted back to tuple as desired in the output format.

As you are a beginner to python, it is strongly recommended to master list comprehensions. It is way too powerful and concise. In addition to making your code more 'pythonic', list comprehensions can act as a friendlier replacement to 'map' and 'filter' functions.

Upvotes: 0

John La Rooy
John La Rooy

Reputation: 304355

from operator import add
list3 = map(add, list1, list2)

Upvotes: 4

ﾠﾠﾠ
ﾠﾠﾠ

Reputation: 67010

Use the power of the zip function and list comprehensions:

list1 = [('a', ),
        ('b', 'c'),
        ('d', 'e'),
        ('f', 'g', 'h') ]

list2 = [('p', 'q'),
        ('r', 's'),
        ('t', ),
        ('u', 'v', 'w') ]

print [a + b for a, b in zip(list1, list2)]

Upvotes: 19

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