Pythonic conversion to singleton iterable if not already an iterable

Question

Suppose I have

def distance2(vector1, vector2):
    zipped = zip(vector1, vector2)
    difference2 = [(vector2 - vector1) ** 2 for (vector1, vector2) in zipped]
    return sum(difference2)

where distance2(vector1, vector2) finds the (squared) Euclidian distance between vector1 and vector2. The function will work for iterable elements, but suppose we also want to make it work for non-iterable elements (i.e. distance2(1,3)). Is there a pythonic way to do this? (i.e, automatically turning regular input into a singleton list).

Answer 1

You are describing the basic usage of always_iterable.

>>> from more_itertools.more import always_iterable
>>> for val in always_iterable(1):
...     print(val)
...     
1

Answer 2

You can use numpy:

np.atleast_1d(1)
# array([1])

np.atleast_1d([1,2,3])
# array([1,2,3])