How to test if an object is iterable on python 2.5+ on all platforms?

Question

I discovered that on Debian with Python 2.5.5 the collections module does not have Iterable class.

Example: http://python.codepad.org/PxLHuRFx

The same code executed on OS X 10.8 with Python 2.5.6 this works, so I assume that this is missing for some reason.

What workaround do I have to make my code pass this on all Python 2.5+ ?

Duplicate of this question: http://stackoverflow.com/questions/1952464/in-python-how-do-i-determine-if-an-object-is-iterable which has an answer. — phkahler, Nov 19 '12 at 17:58

score 4 · Answer 1 · answered Nov 19 '12 at 17:57

4

I would check to see if the object has an __iter__ function defined.

So hasattr(myObj, '__iter__')

answered Nov 19 '12 at 17:57

inspectorG4dget

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@thewolf: Perhaps a `__getitem__` if there isn't an `_iter__`? – inspectorG4dget Nov 19 '12 at 19:04
1

I think the only reliable way is `try: / iter(obj) / except: TypeError` – the wolf Nov 19 '12 at 23:07

score 0 · Answer 2 · edited May 23 '17 at 12:23

This works:

def f(): pass
import sys  
results={'iterable':[],'not iterable':[]}

def isiterable(obj):
    try:
        it=iter(obj)
        return True
    except TypeError:
        return False


for el in ['abcd',[1,2,3],{'a':1,'b':2},(1,2,3),2,f,sys, lambda x: x,set([1,2]),True]:
    if isiterable(el):
        results['iterable'].append('\t{}, a Python {}\n'.format(el,type(el).__name__))
    else:   
        results['not iterable'].append('\t{}, a Python {}\n'.format(el,type(el).__name__))

print 'Interable:'
print ''.join(results['iterable'])

print 'Not Interable:'
print ''.join(results['not iterable'])

Prints:

Interable:
    abcd, a Python str
    [1, 2, 3], a Python list
    {'a': 1, 'b': 2}, a Python dict
    (1, 2, 3), a Python tuple
    set([1, 2]), a Python set

Not Interable:
    2, a Python int
    <function f at 0x100492d70>, a Python function
    <module 'sys' (built-in)>, a Python module
    <function <lambda> at 0x100492b90>, a Python function
    True, a Python bool

This is more fully explored on this SO post.

How to test if an object is iterable on python 2.5+ on all platforms?

2 Answers2