Combining 2 lists in python

Question

I have 2 lists each of equal size and am interested to combine these two lists and write it into a file.

alist=[1,2,3,5] 
blist=[2,3,4,5] 

--the resulting list should be like [(1,2), (2,3), (3,4), (5,5)]

After that i want that to be written it to a file. How can i accomplish this?

Answer 1

# combine the lists
zipped = zip(alist, blist)

# write to a file (in append mode)
file = open("filename", 'a') 
for item in zipped:
    file.write("%d, %d\n" % item) 
file.close()

The resulting output in the file will be:

 1,2
 2,3
 3,4
 5,5

Answer 2

For the sake of completeness, I'll add to Ben's solution that itertools.izip is preferable especially for larger lists if the result is used iteratively, as the final result is not an actual list but a generator:

from itertools import izip
zipped = izip(alist, blist)
with open("output.txt", "wt") as f:
    for item in zipped:
        f.write("{0},{1}\n".format(*item))

The documentation for izip can be found here .