Question

I’m trying to parse a tuple of the form:

a=(1,2)

or

b=((1,2), (3,4)...)

where for a’s case the code would be:

x, y = a

and b would be:

for element in b:
    x, y = element

is there an fast and clean way to accept both forms? This is in a MIDI receive callback
(x is a pointer to a function to run, and y is intensity data to be passed to a light).

Answer 1

# If your input is in in_seq...
if hasattr(in_seq[0], "__iter__"):
    # b case
else:
    # a case

This basically checks to see if the first element of the input sequence is iterable. If it is, then it’s your second case (since a tuple is iterable), if it’s not, then it’s your first case.

If you know for sure that the inputs will be tuples, then you could use this instead:

if isinstance(in_seq[0], tuple):
    # b case
else:
    # a case

Depending on what you want to do, your handling for the ‘a’ case could be as simple as bundling the single tuple inside a larger tuple and then calling the same code on it as the ‘b’ case, e.g…

b_case = (a_case,)

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Edit: as pointed out in the comments, a better version might be…

from collections import Iterable
if isinstance(in_seq[0], Iterable):
    # ...