for i in l:
    f.write("%s %d %d %dn" % tuple(i))

outstring = "n".join(["%s %d %d %d" % tuple(i) for i in l])
f.write(outstring)

import json
json.dumps(l)

outstr = json.dumps(mylist)[1:-1].replace("], ","]n").replace(",","")

outstr = "n".join(["%s %d %d %d" % tuple(i) for i in mylist])

["%s " % item for item in l]

l = [['+1', 12, 13, 14], ['+1', 13, 14, 15]]

f = open("your_file.txt", 'w')

for item in l:
    f.write('[')
    for elem in item[:-1]:
        f.write("{}, ".format(elem))
    f.write("{}".format(item[-1]))
    f.write(']n')