Deep comparison of dicts - cmp() versus ==?

[Ben Finney]

Victor Hooi <victorhooi at gmail.com> writes:

> What is the currently most Pythonic way for doing deep comparisons
> between dicts?

What distinction do you intend by saying “deep comparison”? As
contrasted with what?

> For example, say you have the following two dictionaries
>
> a = {
>         'bob': { 'full_name': 'bob jones', 'age': 4, 'hobbies': ['hockey', 'tennis'], 'parents': { 'mother': 'mary', 'father', 'mike'}},
>         'james': { 'full_name': 'james joyce', 'age': 6, 'hobbies': [],}
> }
>
> b = {
>         'bob': { 'full_name': 'bob jones', 'age': 4, 'hobbies': ['hockey', 'tennis']},
>         'james': { 'full_name': 'james joyce', 'age': 5, 'hobbies': []}
> }

Those two dicts are not equal. How would your intended “deep comparison”
behave for those two values?

> However, this page seems to imply that cmp() is deprecated?
> https://docs.python.org/3/whatsnew/3.0.html#ordering-comparisons

It is, yes.

> Should we just be using the equality operator ("==") instead then? E.g.:
>
> a == b

Yes. That is a comparison that would return False for comparing the
above two values. Would you expect different behaviour?

> What is the reason for this?

I don't really understand. ‘cmp’ is deprecated, and you can compare two
dicts with the built-in operators. That's the reason; are you expecting
some other reason?

> Or is there a better way to do this?

I don't really know what it is you want to do. What behaviour different
from the built-in comparison operators do you want?

-- 
 \         “I went over to the neighbor's and asked to borrow a cup of |
  `\       salt. ‘What are you making?’ ‘A salt lick.’” —Steven Wright |
_o__)                                                                  |
Ben Finney