CODEWITHSUNDEEP
python
kukuruza
kukuruza

Reputation: 111

Python extract list of unknow length

I have a string from user. It must containt a comma to split by it and assign to variables. But what if user miss a comma? Surely I can check len of splitted string in if-else branches, but maybe there is another way, I mean assignment during list has a values. For example

a, b, c, d, e = list(range(3))  # 'a' and 'b' are None or not exists

Upvotes: 0

Views: 76

Answers (2)

Alex.Kh
Alex.Kh

Reputation: 612

You could do something like this:

>>> alist=list(range(3))
>>> alist
[0, 1, 2]
>>> a,b,c,*d=alist
>>> a,b,c
(0, 1, 2)
>>> d
[]

If there are no more elements, d is an empty list. It uses the unpacking operator *. Not the best possible solution for large lists, so I would still define a function for that. For small cases, it works well. (You could assume that is d==[], there are no more elements in alist)For example, you could add:

return False if not d else return True

Upvotes: 1

Hielke Walinga
Hielke Walinga

Reputation: 2845

You are free to extend the list with None values before extraction.

li = list(range(3))
expected_size = 5
missing_size = expected_size - len(li)
none_li = [None] * missing_size
new_li = li + none_li
a, b, c, d, e = new_li

Upvotes: 0

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