Iterate through multiple lists at the same time

Question

Is it possible to iterate through multiple lists and return arguments from different lists within the same loop?

I.e., Instead of -

For x in trees:
  Print(x) 
For y in bushes:
  Print(y)

Something like -

For x,y in trees,bushes:
  Print(x +"\n"+ y)

And also http://stackoverflow.com/questions/126524/iterate-a-list-as-tuples-in-python and http://stackoverflow.com/questions/1210396/how-do-i-iterate-over-the-tuples-of-the-items-of-two-or-more-lists-in-python and probably many more ... :-) — mgilson, Sep 10 '15 at 21:36

score 8 · Accepted Answer · answered Sep 10 '15 at 21:30

8

You can simply use zip or itertools.izip:

for x, y in zip(trees, bushes):
  print x, y

answered Sep 10 '15 at 21:30

juanchopanza

1

python2.x also has [`future_builtins.zip`](https://docs.python.org/2/library/future_builtins.html#future_builtins.zip) which is handy for writing code that works on python2.x and 3.x (Just guard the import statement with a `try: ... except ImportError: pass` suite). – mgilson Sep 10 '15 at 21:34
@mgilson Good point. Python 2.x where x >= 6. – juanchopanza Sep 10 '15 at 21:42
Oh, did python exist in earlier versions than that ;-). I can't seem to remember ... – mgilson Sep 10 '15 at 21:45
@mgilson I still run into systems that are on older versions than 2.6. It is painful. – juanchopanza Sep 10 '15 at 21:46

score 2 · Answer 2 · answered Sep 10 '15 at 21:32

2

You can use zip():

a=['1','2','2']
b=['3','4','5']

for x,y in zip(a,b):
     print(x,y)

output:

1 3

2 4

2 5

answered Sep 10 '15 at 21:32

jlnabais

2 Answers2