Default values for iterable unpacking

Question

I\'ve often been frustrated by the lack of flexibility in Python\'s iterable unpacking.

Take the following example:

a, b = range(2)

Answer 1

Here's an alternative version of the decorator solution by @supersam654, using iterators rather than lists for efficiency:

def variable_return(max_values, default=None):
    def decorator(f):
        def wrapper(*args, **kwargs):
            actual_values = f(*args, **kwargs)
            try:
                for count, value in enumerate(actual_values, 1):
                    yield value
            except TypeError:
                count = 1
                yield actual_values
            yield from [default] * (max_values - count)
        return wrapper
    return decorator

It's used in the same way:

@variable_return(3)
def ret_n(n):
    return tuple(range(n))

a, b, c = ret_n(2)

This could also be used with non-user-defined functions like so:

a, b, c = variable_return(3)(range)(2)