Generators

generators.py

# return a generator instead of a list
def interesting_lines(file):
    for fline in file:
        fline = fline.strip()
        if fline.startswith('#'):
            continue
        if not fline:
            continue
        yield fline

with open('file.ini') as file:
    for line in interesting_lines(file):
        print(line)


# Make an object iterable
class ToDoList:
    def __init__(self):
        self.tasks = []

    def __iter__(self):
        return iter(self.tasks)

todo = ToDoList()
for task in todo:
    print(task)