Python: Efficient unrolling/flattening list of tuples and single floats

I have a list of tuples and single floats

v = [(1., 2., 3.), (4., 5.), 6., 7.]

Now I want to flatten it with the good old list comprehension

[item for sublist in v for item in sublist]

But an error occurs as single floats are not iterable. What is the most efficient way to unroll this mixed list? I tried to go through the list and use isininstance() but once again, the list is not iterable.

EDIT: time comparisons so far

numpy approach with hstack: 6.49 µs ± 100 ns per loop
hasattr approach: 398 ns ± 2.11 ns per loop
collections approach: 804 ns ± 1.27 ns per loop

Solution

You can use hasattr to check if the object is iterable (has a __iter__ method):

out = [item for sublist in v
       for item in (sublist if hasattr(sublist, '__iter__') else [sublist])]

output: [1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0]

An alternative would be to use collections.abc:

from collections.abc import Iterable
    
out = [item for sublist in v
       for item in (sublist if isinstance(sublist, Iterable) else [sublist])]

Note that in both cases, strings are considered iterable, you might want to check for this specific case depending on your data.