for line in sys.stdin.readlines(): fields = line.split("\t") for field in fields[:250]: file1.write(field + '\t') file1.write('\n') It's just taking the first 250 elements of a list and writing them ...

Defining a list in Python is easy—just use the bracket syntax to indicate items in a list, like this: list_of_ints = [1, 2, 3] Items in a list do not have to all be the same type; they can be any ...