Object is Iterable, Then Not Iterable

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February 19th, 2013, 02:40 PM

JohnPetrucci00

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Object is Iterable, Then Not Iterable

Clearly I'm confused as my code appears to iterate properly, then I receive the error:

"TypeError: 'NoneType' object is not iterable"

This is essentially what I have:

Code:

def findOriginalDBMatch(newPartDef, checkIndex, dbPartDef):

    for j in range(len(dbPartDef)):
        if dbPartDef[j].isGeometry():
            print(dbPartDef[j].getPartName())
            if newPartDef[checkIndex].getClosestMatch() == dbPartDef[j].getNameSweep1():
                return j, dbPartDef[j].getPartName()

for i in range(len(newPartDefinitions)):
    print(len(dbFullPartDefinitions))
    if newPartDefinitions[i].isGeometry():
        #print(newPartDefinitions[i].getPartName())
        matchIndex, matchName = findOriginalDBMatch(newPartDefinitions, i, dbFullPartDefinitions)

The last line with 'matchIndex, matchName' is causing the error. I am confused because the print command in the 'findOriginalDBMatch' function prints many times before the program crashes. In the function call, 'newPartDefinitions' and 'dbFullPartDefinitions' are lists of objects.

I'm at a loss right now, so please let me know what other info is helpful.

Thanks.

-John

February 19th, 2013, 03:16 PM

JohnPetrucci00

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I think I have figured it out - in certain cases the function did not have inputs that met criteria for it to return something. The error message seems a little confusing/misleading to me.

February 19th, 2013, 03:22 PM

b49P23TIvg

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Python functions always return something.
If you don't specify the "something" the return value is None .

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February 19th, 2013, 04:02 PM

JohnPetrucci00

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Thanks for the response. So the "'NoneType' object" that the error message refers to actually is what is returned by the function? Is it saying it should be iterable because I am expecting the function to return multiple values?

February 19th, 2013, 04:53 PM

b49P23TIvg

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>>> (a,b,) = None
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not iterable

Quote:

Originally Posted by John

Is it saying it should be iterable because I am expecting the function to return multiple values?

Likely!

February 22nd, 2013, 10:02 AM

BadOmen

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typo

if you want a function to return multiple values, be itterable.
you have to use yield instead of return.

Code:

def testItter():
  for i in range(1,10):
    yield i

for i in testItter():
  print i

Object is Iterable, Then Not Iterable

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