Question

I have this piece of code which creates a note and adds to the notebook. When I run this I get a Iteration over non-sequence error.

import datetime
class Note:
    def __init__(self, memo, tags):
        self.memo = memo
        self.tags = tags
        self.creation_date = datetime.date.today()

def __str__(self):
    return 'Memo={0}, Tag={1}'.format(self.memo, self.tags)


class NoteBook:
     def __init__(self):
        self.notes = []

     def add_note(self,memo,tags):
        self.notes.append(Note(memo,tags))

if __name__ == "__main__":
    firstnote = Note('This is my first memo','example')
    print(firstnote)
    Notes = NoteBook()
    Notes.add_note('Added thru notes','example-1')
    Notes.add_note('Added thru notes','example-2')
    for note in Notes:
        print(note.memo)

Error:

C:\Python27\Basics\OOP\formytesting>python notebook.py  
Memo=This is my first memo, Tag=example  
Traceback (most recent call last):  
  File "notebook.py", line 27, in   
    for note in Notes:  
TypeError: iteration over non-sequence

Answer 1

You are trying to iterate over the object itself, which is returning the error. You want to iterate over the list inside the object, in this case Notes.notes (which is somewhat confusing naming, you may want to distinguish the internal list by using another name for the instance of the notebook object).

for note in Notes.notes:
    print(note.memo)