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+--- Thread: Problem in flattening list (/thread-26465.html)
Problem in flattening list - Shahmadhur13 - May-02-2020
I tried to flatten list.I have nested list and i want all iterables of that nested list in one list without any nested list. Itried with itertool.chain and also with recursive function.
import itertools a = [[1,2,3], [4,7,8],9] b = list(itertools.chain(a)) print(b)
def flatten(list): a=[] for i in list: if type(i) == list: flatten(i) else: a.append(i) return a b = [[1,2,3], [4,7,8],9] c = flatten(b) print(c)I still get nested list in result. No changes
RE: Problem in flattening list - pyzyx3qwerty - May-02-2020
Go through this page
RE: Problem in flattening list - bowlofred - May-02-2020
I'd probably do it this way.
a = [[1,2,3], [4,7,8],9]
l = []
for item in a:
if isinstance(item, list):
l.extend(item)
else:
l.append(item)
print(l)Output:[1, 2, 3, 4, 7, 8, 9]RE: Problem in flattening list - DeaD_EyE - May-02-2020
It's good to know how to implement this without external dependencies.
Later you should take a look into
more_itertools, after you now itertools.https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.flatten
RE: Problem in flattening list - bowlofred - May-02-2020
I'd prefer to use a nice library, but the flatten in more-itertools unpacks all the elements in the list exactly one level. It won't cope with the
9 in the OP list.
RE: Problem in flattening list - DeaD_EyE - May-03-2020
Quote:See also collapse(), which can flatten multiple levels of nesting.