On Thursday, July 25, 2019 at 9:57:38 PM UTC-5, Chris Angelico wrote:
> On Fri, Jul 26, 2019 at 12:46 PM DT <dennistob...@gmail.com> wrote:
> > def main():
> > ap_list = []
> > ap_dict = {}
> >
> > for row in csv_reader:
> > ap_dict['ap_name'] = ap.name
> > ap_dict['ap_ipv4'] = ap.ipv4
> > ap_dict['ap_model'] = ap.model
> > ap_dict['ap_location'] = ap.location
> >
> > ap_list.append(ap_dict)
> >
> > print(ap_list)
> >
> >
> > When I execute print(ap_list) I get the very last row in the CSV repeated
> > once for every row in the file. I would expect to see a list of ap_dicts,
> > but I do not. When I add print(ap_dict) directly after the
> > ap_list.append(ap_dict) inside the loop I see the correct values. Why is it
> > that the print(ap_list) that happens outside of the for loop is only
> > printing the last item on repeat?
> >
>
> You create one dictionary, and then reuse it every time. Appending it
> to a list doesn't change it, which means you keep overwriting the same
> dictionary every time you go through the loop.
>
> Try creating a new dictionary for each row; in fact, you can simplify
> things significantly by using a dict literal (or, more technically,
> "dict display") to create a new dictionary with the four fields
> already set. You could even do that in the same operation as appending
> to the list.
>
> ChrisA
That is interesting to know. I guess I was confused because when I put in a
print(ap_dict) in the for loop, it printed out the contents of the dict
correctly for each pass. I assumed that when I then added that dict into the
list that the list would be appended with that iterations values. I guess I
have a bit to learn about how things are referenced in Python.
Thanks for the hint. I updated my code and it works correctly now.
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