Is bug or not?

[Cassie]

Hi, I'm having a trouble with new Python 3.7 when use next code, I have got next raise Exception StopIteration, but I have not it when use 2.7.

def _zip(*args):
    iters = list(map(iter, args))
    while iters:
        res = [next(i) for i in iters]
        yield tuple(res)


if __name__ == '__main__':
    s1, s2 = 'abc', 'xyz123'
    print(list(_zip(s1, s2)))

thanks in advance.

[stranac]

It's not a bug, the behavior was just changed in python 3.5
You can read more at https://www.python.org/dev/peps/pep-0479/

[DeaD_EyE]

I know you made this function as demonstration.
Here an example which works with Python 2.7 and Python 3.7:

from __future__ import print_function
import sys


def _zip1(*args):
    iters = list(map(iter, args))
    while iters:
        res = [next(i) for i in iters]
        yield tuple(res)

def _zip2(*args):
    for i in zip(*args):
        yield tuple(i)


if __name__ == '__main__':
    print('Python Version:', sys.version)
    s1, s2 = 'abc', 'xyz123'
    print('Your example:')
    try:
        print(list(_zip1(s1, s2)))
    except Exception as e:
        print(e)
    print('Modified version:')
    print(list(_zip2(s1, s2)))

Output:
deadeye@nexus ~ $ python w.py 
Python Version: 3.7.0 (default, Jun 28 2018, 17:48:59) 
[GCC 8.1.1 20180531]
Your example:
generator raised StopIteration
Modified version:
[('a', 'x'), ('b', 'y'), ('c', 'z')]
deadeye@nexus ~ $ python2 w.py 
Python Version: 2.7.15 (default, Jun 27 2018, 13:05:28) 
[GCC 8.1.1 20180531]
Your example:
[('a', 'x'), ('b', 'y'), ('c', 'z')]
Modified version:
[('a', 'x'), ('b', 'y'), ('c', 'z')]

The modified function is even shorter and easier to understand.
Have a nice weekend.

[Cassie]

thanks for replies