Reference library

Lists & loops

Iterate, transform, and combine sequences with readable loop patterns.

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Lists & loops easy

How to Flatten a Deeply Nested List in Python Recursively

A recursive function that flattens arbitrarily deep nested lists into a single flat list using isinstance checks.

recursion flatten lists
Python 
def flatten(nested_list):
    if not nested_list:
        return []
    if isinstance(nested_list[0], list):
        return flatten(nested_list[0]) + flatten(nested_list[1:])
    return [nested_list[0]] + flatten(nested_list[1:])


if __name__ == "__main__":
    data = [1, [2, [3, [4, [5]]]], [6, [7, [8, [9]]]], 10]
 …
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Lists & loops — Python code examples

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