How to reverse order of keys in python dict?

Try:

for i in sorted(a.keys(), reverse=True):
    print i

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'}

for i in reversed(sorted(a.keys())):
    print i

Python dictionaries don’t have any ‘order’ associated with them. It’s merely a ‘coincidence’ that the dict is printing the same order. There are no guarantees that items in a dictionary with come out in any order.

If you want to deal with ordering you’ll need to convert the dictionary to a list.

a = list(a) # keys in list
a = a.keys() # keys in list
a = a.values() # values in list
a = a.items() # tuples of (key,value) in list

Now you can sort the list as normal, e.g., a.sort() and reverse it as well, e.g., a.reverse()

Python dict is not ordered in 2.x. But there’s an ordered dict implementation in 3.1.

just try,

INPUT: a = {0:’000000′,1:’11111′,3:’333333′,4:’444444′}

[x for x in sorted(a.keys(), reverse=True)]

OUTPUT: [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:

b
c
a

Since Python 3.8, the built-in function reversed() accepts dicts as well.

Here’s an example of how you can use it to iterate:

my_dict = {'a': 1, 'c': 3, 'b': 2}

for k in reversed(my_dict):
    print(k)

Here’s an example of how you can replace your dict with a reversed dict:

my_dict = dict(reversed(my_dict.items()))

In Python 3.6, which I am using, I reversed the order of keys with their respective values with the help of function update.

original_dict={'A':0,'C':2,'B':1}
new_dict={}
for k,v in original_dict.items():
    dict_element={k:v}
    dict_element.update(new_dict)
    new_dict=dict_element

print(new_dict)

It should print out:

{'B':1,'C':2,'A':0}

My 2 ¢.

If you want to preserve the insertion order and not the alphabetical ordering, then you can use:

dict(list(your_dict.keys())[::-1])

Or for the whole dictionary:

dict(list(your_dict.items())[::-1])

If you have a dictionary like this

{'faisal2': 2, 'umair': 2, 'fais': 1, 'umair2': 1, 'trending': 2, 'apple': 2, 'orange': 2}

and you want to reverse sort dictionary you can use:

dict(sorted(counts.items(), key=lambda item: item[1],reverse=True))

output will be:

{'faisal2': 2, 'umair': 2, 'trending': 2, 'apple': 2, 'orange': 2, 'fais': 1, 'umair2': 1}