suggestions, comments on an "is_subdict" test

Fri Apr 22 10:29:48 EDT 2011

On 22/04/2011 14:55, Vlastimil Brom wrote:
> Hi all,
> I'd like to ask for comments or advice on a simple code for testing a
> "subdict", i.e. check whether all items of a given dictionary are
> present in a reference dictionary.
> Sofar I have:
>> def is_subdict(test_dct, base_dct):
> """Test whether all the items of test_dct are present in base_dct."""
> unique_obj = object()
> for key, value in test_dct.items():
> if not base_dct.get(key, unique_obj) == value:
> return False
> return True
>> I'd like to ask for possibly more idiomatic solutions, or more obvious
> ways to do this. Did I maybe missed some builtin possibility?
> I am unsure whether the check against an unique object() or the
> negated comparison are usual.?
> (The builtin exceptions are ok, in case anything not dict-like is
> passed. A cornercase like>>> is_subdict({}, 4)
>>>> True
> doesen't seem to be worth a special check just now.)
>You could shorten it slightly to:
def is_subdict(test_dct, base_dct):
 """Test whether all the items of test_dct are present in base_dct."""
 unique_obj = object()
 return all(base_dct.get(key, unique_obj) == value for key, value in 
test_dct.items())