CODEWITHSUNDEEP
pythonlistdictionary
JamesHudson81
JamesHudson81

Reputation: 2273

getting the keys of a dict based on the values which are a list

I have a list1 of values:

['A','B','C','D']

And I have a dict 

{1: ['A','F'],2:['B','J'],3:['C','N'],4:['D','X']}

I would like to obtain the key for every value in the list:

I tried :

[dict1[x] for x in list]

However ouputs an error because I am not considering the fact the dict value is a list not a single value. How could I achieve this?

My desired output would be a list with the keys of the list1 values:

[1,2,3,4]

Upvotes: 3

Views: 44

Answers (2)

Austin
Austin

Reputation: 26039

You can use a list-comprehension:

[k for x in lst for k, v in d.items() if x in v]

Example:

lst = ['A','B','C','D']
d = {1: ['A','F'],2:['B','J'],3:['C','N'],4:['D','X']}

print([k for x in lst for k, v in d.items() if x in v])
# [1, 2, 3, 4]

Upvotes: 5

Ajax1234
Ajax1234

Reputation: 71451

You can flatten the dictionary and use it as a lookup:

data = ['A','B','C','D']
d = {1: ['A','F'],2:['B','J'],3:['C','N'],4:['D','X']}
new_d = {i:a for a, b in d.items() for i in b}
result = [new_d[i] for i in data]

Output:

[1, 2, 3, 4]

Upvotes: 4

Related Questions