[Tutor] I get an error while search in my Entry field

[Peter Otten]

Alan Gauld via Tutor wrote:

> On 17/06/18 23:59, Ali M wrote:
> 
>>     def update_list(self):
>>         search_term = self.search_var.get()
>>         self.listbox.delete(0, tk.END)
>>         for item in self.listbox:
> 
> The above pair of lines look odd.
> You delete everything on the listbox then try to iterate
> over it? Is that really what you want?

More likely the words have to be reread from the database.
  
> Also are you sure you can iterate over a listbox widget?
> I was not aware of that capability and can see nothing
> about iterators in the listbox help screen...

You cannot iterate over Listbox widgets, it's just that for every object 
with a __getitem__() method Python will try and feed it consecutive integers

>>> class A:
...     def __getitem__(self, index):
...         if index > 3: raise IndexError
...         return index * index
... 
>>> list(A())
[0, 1, 4, 9]

a feature that probably predates the iterator protocol.
However, the tkinter widgets expect option names like "background", or 
"borderstyle", and respond with the somewhat cryptic TypeError when the 0 is 
passed instead.
 
> I usually use the get() method to fetch the contents
> before trying to iterate over them:
> 
> for item in myList.get(0,tk.END):
>    # use item
>