iterating over N lists in parallel

[Skaperen]

i had been thinking this might be a nice feature but i am wondering if this could be done with a generator.  the original idea was:

for a,b,c in [1,2],['three','four'],['foo','bar']:
    print(a,b,c)

Output:
1 three foo
2 four bar

it would be parallel iteration over 3 separate lists of the same length.  if the lengths differ iteration stops at the end of the shortest one.

could this be done with any iterator?

Moderator Kebap: Moved thread to General Coding

[Kebap]

Do you know python zip()?

[Skaperen]

there i go again, not knowing the right words to search, although i didn't do it recently. i guess it is best for each thing i need to do in python is assume it has already been done. i guess i got this from C experience, where almost nothing had been done, and from assembler 360 experience where there was even less.

[ankit]

The length of each list should be equal to or more than the no of values we provide (a,b,c...)

for a,b,c in [1,2,3],[4,5,6],[7,8,9]:
      print (a,b,c)

the output is:
(1, 2, 3)
(4, 5, 6)
(7, 8, 9)

this is no need to use same data type ,any data type can be used as list member.

[Skaperen]

The length of each list should be equal to or more than the no of values we provide (a,b,c...)

for a,b,c in [1,2,3],[4,5,6],[7,8,9]:
      print (a,b,c)

the output is:
(1, 2, 3)
(4, 5, 6)
(7, 8, 9)

this is no need to use same data type ,any data type can be used as list member.

what i am wanting is for the 3 lists to be iterated in parallel so that the first iteration gets [1,4,7].

Output:
lt1/forums /home/forums 11> py3
Python 3.5.2 (default, Nov 17 2016, 17:05:23) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> for x in zip([1,2,3],[4,5,6],[7,8,9]):
...     print(x)
... 
(1, 4, 7)
(2, 5, 8)
(3, 6, 9)
>>> 
lt1/forums /home/forums 12> 

this is exactly what i was looking for.  the name probably comes from the action of a zipper for the case of 2 iterators.  this will let me iterate over N lists in parallel without using indexes or constructing a list of N-tuples.

[Skaperen]

i wrote a little script using zip() ... not what i was originally thinking about this for.  it is in Scripts & Snippets.

[buran]

Just for sake of completeness and to the benefit of Python2 users - in Python2 zip returns list, while in itertools.izip() returns iterator. In Python3 zip returns iterator and itertools.izip() is not available.
Also Python2 has itertools.izip_longest () and in Python3 there is itertools.zip_longest() to process iterables of unequal size and option to provide a fill value for shorter one(s).