List=[[1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11, 12, 15]]

[1, 2, 3]
[4, 5, 6, 7]
[8, 9, 10, 11, 12, 15]

1, 2, 3
4, 5, 6, 7
8, 9, 10, 11, 12, 15

file.write(','.join(map(repr, List[i]))

file.write(str(List[i]))

'[' + ', '.join(map(repr, self)) + ']'

','.join(map(repr, self))

import csv
with open('/tmp/myfile.txt', 'w') as f:
    csv_writer = csv.writer(f)
    csv_writer.writerows(List)

from __future__ import print_function # ignore if on py 3.x

for line in List:
    print(*line, sep=',', file=file)

print 'n'.join(','.join(map(str, x)) for x in List)

print(fd.read().split('n')[:1])

['(information)']

fd = open('examplefile.txt', 'r+')
    print(fd.read().split('n')[1-1])
    fd = open('examplefile.txt', 'r+')
    print(file2 = fd.read().split('n')[2-3])

(information1)
    (information2)

fd = open('examplefile.txt', 'r+')
    print(fd.read().split('n')[1-1])
    print(file2 = fd.read().split('n')[2-3])

(information1)