How to reverse order of keys in python dict?
The order keys are iterated in is arbitrary. It was only a coincidence that they were in sorted order.
>>> a = {0:'000000',1:'11111',3:'333333',4:'444444'}>>> a.keys()[0, 1, 3, 4]>>> sorted(a.keys())[0, 1, 3, 4]>>> reversed(sorted(a.keys()))<listreverseiterator object at 0x02B0DB70>>>> list(reversed(sorted(a.keys())))[4, 3, 1, 0]
Since Python 3.7 dicts preserve order, which means you can do this now:
my_dict = {'a': 1, 'c': 3, 'b': 2}for k in reversed(list(my_dict.keys())): print(k)Output:
bcaSince Python 3.8 the built-in reversed() accepts dicts as well, thus you can use:
for k in reversed(my_dict): print(k)
Dictionaries are unordered so you cannot reverse them. The order of the current output is arbitrary.
That said, you can order the keys of course:
for i in sorted(a.keys(), reverse=True): print a[i];but this gives you the reverse order of the sorted keys, not necessarily the reverse order of the keys how they have been added. I.e. it won't give you 1 0 3 if your dictionary was:
a = {3:'3', 0:'0', 1:'1'}