LEN error for zipping in python

Question

def shufflemode():
    import random
    combined = zip(question, answer)
    random.shuffle(combined)
    question[:], answer[:] = zip(*combined)

but then i get the error: TypeError: object of type 'zip' has no len()

What do I do im so confused

Did you import a type named "zip" which overrides the buildin zip function? — nicky_zs, Aug 05 '13 at 01:45
Does this answer your question? [Python 2 --> 3: object of type 'zip' has no len()](https://stackoverflow.com/questions/31011631/python-2-3-object-of-type-zip-has-no-len) — ggorlen, Aug 05 '21 at 14:47

score 1 · Answer 1 · edited May 23 '17 at 12:10

1

I wonder the same thing. According to: randomizing two lists and maintaining order in python You should be able to do it like the OP tried, but i also get the same error. I think the ones from the link are using python 2 and not 3, could this be the problem?

edited May 23 '17 at 12:10

Community

1
1

answered Aug 17 '13 at 00:55

user2691056

11
1

This was working for me in Python 2.7 but now that I've changed to Python3 the same code encounters an error. Zip should has changed from python2 to 3. – armen Dec 01 '15 at 18:37

score 1 · Answer 2 · edited May 23 '17 at 10:30

This is an issue between Python 2 and Python 3. In Python 2 using shuffle after zip works, because zip returns a list. In Python 3: "TypeError: object of type 'zip' has no len()" because zip returns an iterator in Python 3.

Solution, use list() to convert to a list:

combined = list(zip(question, answer))
random.shuffle(combined)

The error appeared with shuffle() because shuffle() uses len().

References issue: The zip() function in python 3

score 0 · Answer 3 · answered Jan 08 '14 at 22:00

Stumbled upon this and was surprised to learn about the random.shuffle method. So I tried your example, and it worked for me in Python 2.7.5:

def shufflemode():
    import random
    combined = zip(question, answer)
    random.shuffle(combined)
    question[:], answer[:] = zip(*combined)

question = ["q1","q2","q3","q4","q5"]
answer = ["a1","a2","a3","a4","a5"]

if __name__ == "__main__":
    shufflemode()
    print question,answer

The result is two lists with the same randomized sequence of questions and answers*strong text*:

>>> 
['q3', 'q2', 'q5', 'q4', 'q1'] ['a3', 'a2', 'a5', 'a4', 'a1']
>>>

LEN error for zipping in python

3 Answers3

Linked