Python dictionary: are keys() and values() always the same order?

Question

It looks like the lists returned by keys() and values() methods of a dictionary are always a 1-to-1 mapping (assuming the dictionary is not altered between calling the 2 methods).

For example:

>>> d = {'one':1, 'two': 2, 'three': 3} >>> k, v = d.keys(), d.values() >>> for i in range(len(k)):     print d[k[i]] == v[i]  True True True 

If you do not alter the dictionary between calling keys() and calling values(), is it wrong to assume the above for-loop will always print True? I could not find any documentation confirming this.

Answer 1

Found this:

If items(), keys(), values(), iteritems(), iterkeys(), and itervalues() are called with no intervening modifications to the dictionary, the lists will directly correspond.

On 2.x documentation and 3.x documentation.

Answer 2

Yes, what you observed is indeed a guaranteed property -- keys(), values() and items() return lists in congruent order if the dict is not altered. iterkeys() &c also iterate in the same order as the corresponding lists.