What is the best way to print a list with 3 sublists to a file in python?

Question

I have a list "localisation" which contains 3 sublists. I want to print this list to a file with each sublist in a column.

eg:

>>>print localisation

localisation = [['a', 'b', 'c'],['d', 'e', 'f'],['g', 'h', 'i']]

I want a file that looks like:

a   d   g
b   e   h
c   f   i

(columns can be separated by a single space, a tab etc)

At the moment I am doing it as follows:

with open("rssi.txt") as fd:
    for item in localisation:
        print>>fd, item

Is there a better way of doing it eg a single line that prints the whole list in at one time?

Answer 1

localisation = [['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']]

with open("rssi.txt") as f:
    f.write('\n'.join(' '.join(row) for row in zip(*localisation)))

# a d g
# b e h
# c f i

>>> localisation = [['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']]
>>> zip(*localisation)
[('a', 'd', 'g'), ('b', 'e', 'h'), ('c', 'f', 'i')]

Answer 2

with open("rssi.txt", "w") as f:
    for col in zip(*localisation):
        f.write(' '.join(str(x) for x in col) + '\n')

If every item in your inner list is already a string you can just use ' '.join(col) + '\\n' , to separate by tabs instead of spaces use '\\t'.join(...) .