Extract all the elements from a list of tuples and put all those unique elements in a list

Question

codes = [('A', ['B', 'C']), ('D', ['E', 'C'])]

Output:

['A', 'B','C','D','E']

Tried Code:

n = 1
e = [x[n] for x in codes]

Does this answer your question? [How do I make a flat list out of a list of lists?](https://stackoverflow.com/questions/952914/how-do-i-make-a-flat-list-out-of-a-list-of-lists) — SuperStormer, Sep 09 '22 at 08:34
then [Get unique values from a list in python](https://stackoverflow.com/q/12897374) — SuperStormer, Sep 09 '22 at 08:35

score 0 · Accepted Answer · answered Sep 09 '22 at 08:36

For the basic case shown there:

tuples = [("A", ["B", "C"]), ("A", ["B", "C"])]

unpacked = []

for current_tuple in tuples:
    # add the first element
    unpacked.append(current_tuple[0])
    # append all elements in the list to the tuple
    unpacked.extend(current_tuple[1])

for nesting of unknown depth

def get_all_elements(from_list) -> list:
    elements = []
    for item in from_list:
        if type(item) == list or type(item) == tuple:
            elements.extend(get_all_elements(item))
        else:
            elements.append(item)
            
    return elements

If all elements have a known and predictable structure e.g. 1st element is a string and 2nd element is a tuple of strings then the first case can be used. Otherwise the more complicated recursive function (second case) is required.

Output elements were not unique hence added below code. It is working now. list(set(unpacked)) — Alpha Beta, Sep 09 '22 at 09:05

score 0 · Answer 2 · answered Sep 09 '22 at 08:41

0

from itertools import chain
list(set(list(chain.from_iterable([val for sublist in list(map(list, zip(*codes))) for val in sublist]))))

answered Sep 09 '22 at 08:41

R. Baraiya

1,490
1
4
17

Extract all the elements from a list of tuples and put all those unique elements in a list

2 Answers2