Posted By: Anonymous
Is there a method like
isiterable? The only solution I have found so far is to call
But I am not sure how fool-proof this is.
__iter__works on sequence types, but it would fail on e.g. strings in Python 2. I would like to know the right answer too, until then, here is one possibility (which would work on strings, too):
from __future__ import print_function try: some_object_iterator = iter(some_object) except TypeError as te: print(some_object, 'is not iterable')
iterbuilt-in checks for the
__iter__method or in the case of strings the
Another general pythonic approach is to assume an iterable, then fail gracefully if it does not work on the given object. The Python glossary:
Pythonic programming style that determines an object’s type by inspection of its method or attribute signature rather than by explicit relationship to some type object (“If it looks like a duck and quacks like a duck, it must be a duck.”) By emphasizing interfaces rather than specific types, well-designed code improves its flexibility by allowing polymorphic substitution. Duck-typing avoids tests using type() or isinstance(). Instead, it typically employs the EAFP (Easier to Ask Forgiveness than Permission) style of programming.
try: _ = (e for e in my_object) except TypeError: print my_object, 'is not iterable'
collectionsmodule provides some abstract base classes, which allow to ask classes or instances if they provide particular functionality, for example:
from collections.abc import Iterable if isinstance(e, Iterable): # e is iterable
However, this does not check for classes that are iterable through