Python: Weird Behavior While Using `yield From`

In the following code, I have run into a RecursionError: maximum recursion depth exceeded. def unpack(given): for i in given: if hasattr(i, '__iter__'): yie

Solution 1:

Strings are infinitely iterable. Even a one-character string is iterable.

Therefore, you will always get a stack overflow unless you add special handling for strings:

defflatten(x):
    try:
        it = iter(x)
    except TypeError:
        yield x
        returnifisinstance(x, (str,  bytes)):
        yield x
        returnfor elem in it:
        yieldfrom flatten(elem)

Note: using hasattr(i, '__iter__') is not sufficient to check if i is iterable, because there are other ways to satisfy the iterator protocol. The only reliable way to determine whether an object is iterable is to call iter(obj).