# python – Comparing two dictionaries and checking how many (key, value) pairs are equal

## python – Comparing two dictionaries and checking how many (key, value) pairs are equal

If you want to know how many values match in both the dictionaries, you should have said that 🙂

Maybe something like this:

``````shared_items = {k: x[k] for k in x if k in y and x[k] == y[k]}
print len(shared_items)
``````

What you want to do is simply `x==y`

What you do is not a good idea, because the items in a dictionary are not supposed to have any order. You might be comparing `[(a,1),(b,1)]` with `[(b,1), (a,1)]` (same dictionaries, different order).

For example, see this:

``````>>> x = dict(a=2, b=2,c=3, d=4)
>>> x
{a: 2, c: 3, b: 2, d: 4}
>>> y = dict(b=2,c=3, d=4)
>>> y
{c: 3, b: 2, d: 4}
>>> zip(x.iteritems(), y.iteritems())
[((a, 2), (c, 3)), ((c, 3), (b, 2)), ((b, 2), (d, 4))]
``````

The difference is only one item, but your algorithm will see that all items are different

#### python – Comparing two dictionaries and checking how many (key, value) pairs are equal

``````def dict_compare(d1, d2):
d1_keys = set(d1.keys())
d2_keys = set(d2.keys())
shared_keys = d1_keys.intersection(d2_keys)