How do I iterate through nested lists in Python?

How do I iterate through nested lists in Python?

You can use a nested loop to iterate through each list within the main list. For example:

nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
for inner_list in nested_list:
    for item in inner_list:
        print(item)

What if I want to access specific elements?

You can access specific elements by using their indices. For example, nested_list[0][1] will give you 2.

Can I use list comprehensions for this?

Yes! You can use a list comprehension to flatten the nested list:

flattened = [item for inner_list in nested_list for item in inner_list]

What about using the itertools module?

You can use itertools.chain to flatten the list as well:

import itertools
flattened = list(itertools.chain.from_iterable(nested_list))