How to transform a list into a CSV file with N items per row?

Question

I want to create a new CSV file with 3 items per row. My source file looks like (there are no new lines / line breaks):

Answer 1

File I/O neutral solution:

csv = """12123, 1324, 232324, 243443, 234, 2345

2334, 2445, 22355, 222234, 2345"""  # replace this with the file you read from CSV

def sixPerLineToThreePerLine(s):
  result = ""
  for line in s.split("\n"):
    sp = line.split(", ")
    result = result + ", ".join(sp[:3]) + "\n" + ", ".join(sp[3:])
  return result

print(sixPerLineToThreePerLine(csv))  # replace this with code to write to CSV