Python to Find number of lists in a tuple

A Python tuple is ordered and unchangeable. It can contain lists as its elements. Given a tuple made up of lists, let's find out how many lists are present in the tuple using different approaches.

Using len() Function

The simplest approach is to use the built-in len() function, which returns the count of elements (lists) in the tuple ?

tupA = (['a', 'b', 'x'], [21, 19])
tupB = (['n', 'm'], ['z', 'y', 'x'], [3, 7, 89])

print("The number of lists in tupA:", len(tupA))
print("The number of lists in tupB:", len(tupB))

The output of the above code is ?

The number of lists in tupA: 2
The number of lists in tupB: 3

Using a User-Defined Function

For reusable code, we can create a function that validates the input and counts the lists ?

tupA = (['a', 'b', 'x'], [21, 19])
tupB = (['n', 'm'], ['z', 'y', 'x'], [3, 7, 89])

def count_lists(input_tuple):
    if isinstance(input_tuple, tuple):
        return len(input_tuple)
    else:
        return "Input is not a tuple"

print("The number of lists in tupA:", count_lists(tupA))
print("The number of lists in tupB:", count_lists(tupB))

The output of the above code is ?

The number of lists in tupA: 2
The number of lists in tupB: 3

Counting Only List Elements

If the tuple contains mixed data types and you only want to count actual list elements ?

mixed_tuple = (['a', 'b'], 42, ['x', 'y'], "hello", [1, 2, 3])

def count_only_lists(input_tuple):
    return sum(1 for item in input_tuple if isinstance(item, list))

print("Total elements:", len(mixed_tuple))
print("Only list elements:", count_only_lists(mixed_tuple))

The output of the above code is ?

Total elements: 5
Only list elements: 3

Comparison

Conclusion

Use len() for simple counting when all tuple elements are lists. For mixed data types or input validation, create a function with type checking to count only list elements accurately.