Python dictionary code

Question

So I need to write a python code for getting all the keys in a dictionary with unique values. For example

my_dict = {4:3, 5:3, 6:4, 9:8}

the program should print

[6, 9]

Because the 3 is repeated in the values. I do not know how to see if the values are different and then how to remove them as there is no ".remove()" for dictionaries. I have tried making a list of keys and values, then trying to mutate them in some way, but I have had no luck. Thanks

PS -- thers is no `.remove()` method for dicts because you are supposed to use `del` as indicated in [the documentation](https://docs.python.org/2/library/stdtypes.html#mapping-types-dict). — Two-Bit Alchemist, Aug 07 '15 at 20:30

Padraic Cunningham · Accepted Answer · 2015-08-07T20:40:33.043

4

Count the values with a collections.Counter dict then only keep keys from you dict with a value that is equal to 1 in the Counter dict.

my_dict = {"4":"3", "5":"3", "6":"4", "9":"8"}


from collections import Counter

cn = Counter(my_dict.itervalues())
print([k for k,v in my_dict.iteritems() if cn[v] == 1])
['6', '9']

edited Aug 07 '15 at 20:40

answered Aug 07 '15 at 20:35

Padraic Cunningham

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@JMacr, no worries, it takes a bit more memory to store the Counter dict but the solution is `O(n) – Padraic Cunningham Aug 07 '15 at 20:41

Python dictionary code

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