Python: AttributeError: ‘_io.TextIOWrapper’ object has no attribute ‘split’

You are using str methods on an open file object.

You can read the file as a list of lines by simply calling list() on the file object:

with open('goodlines.txt') as f:
    mylist = list(f)

This does include the newline characters. You can strip those in a list comprehension:

with open('goodlines.txt') as f:
    mylist = [line.rstrip('\n') for line in f]