CODEWITHSUNDEEP
pythonlistdictionarykey
user3467226
user3467226

Reputation: 81

how to identify keys in dictionary-python

Hi i need to get my program to display only the values that appear as keys and never as values in a dictionary?

i tried and got the values and keys stored in a dictionary and now i don't know how to identify the one that is only a key and never a value

lets say i have dict[('1', '2'), ('1', '3'), ('2', '4'), ('3', '4'), ('5', '6')]

now the only item that only appears as a key and not a value is 1 and 5 so how do i get my program to display

only a key not a value:

    1
    5

Upvotes: 0

Views: 1192

Answers (2)

BrenBarn
BrenBarn

Reputation: 251558

You can do

set(d.keys()) - set(d.values())

Note that your example has a problem (apart from the syntax mistake). You have two tuples with '1' as the first element. A dict can't have the same key twice. The second one will override the first, so ('1', '2') will not make it into the dict, and so '2' is also a key that does not occur as a value.

Upvotes: 3

sshashank124
sshashank124

Reputation: 32197

Why not iterate through the dict as follows:

allowed = [i for i in my_dict if i not in my_dict.values()]

Upvotes: 0

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