How to pair up two lists? [duplicate]

Answer 1

For a one line you can use combination of map() and lambda(). Look here if not familiar to this concepts.

But be careful, you must be with python 3.x so that print is a function and can be used inside the lambda expression.

>>> from __future__ import print_function
>>> l1 = [2,3,4,5]
>>> l2 = [6,7,3,8]
>>> list(map(lambda X: print(X[0],X[1]), list(zip(l1,l2))))

output

2 6
3 7
4 3
5 8

Answer 2

Use the zip function, along with tuple unpacking:

for x, y in zip(xs, ys):
    print x, y

In your case, depending on what you need the xs and ys for, you could have iterated through the csv.reader directly:

with filein as f:
    reader=csv.reader(f)
    for x, y in reader:
        print x, y

The zip(xs, ys) line was effectively reversing your xs, ys = zip(*reader) line.

Answer 3

Use zip:

>>> L=[1,2,3]
>>> M=[4,5,6]
>>> for a,b in zip(L,M):
...   print(a,b)
...
1 4
2 5
3 6