CODEWITHSUNDEEP
pythonarrayssortingdictionary
JAVABB
JAVABB

Reputation: 27

Sort a list by its respective value in a separate dictionary?

Say I have a dictionary and some of the keys are values in a separate array, how do I sort the values in my array by the values for their respective keys in the dictionary?

For example:

input:

dict = {'a': 4, 'b': 7, 'c': 10, 'd': 1}
array = [a, b, d]

output:

array = ['d', 'a', 'b']

The order of the values in the output array would be "d" first because its value in the dictionary was the lowest (1). Followed by "a" (4) and "b" (7). I purposely did not include "c" in the array.

I am not asking for to solve this algorithmically

I am asking if there is a simple built-in way to do this, such as by using sorted(array, key= ) type function.

Upvotes: 0

Views: 36

Answers (3)

Elmar
Elmar

Reputation: 4387

You can try this: dict = {'a': 4, 'b': 7, 'c': 10, 'd': 1} array = ["a", "b", "d"]

new_dict = sorted(dict.items(), key=lambda x: x[1])

output_array = []
for key, value in new_dict:
    check_values = key in array
    if(check_values == True):
        output_array.append(key)

print(output_array)`

Upvotes: 0

user13204959
user13204959

Reputation:

Yes, you can use a lambda function that returns the value of a corresponding element in your dictionary.
By the way, I think it's not a good practice to use the word 'dict' for variable names as it is a built-in word in python. 

print(sorted(array, key=lambda x: a_dict[x]))

Upvotes: 0

wim
wim

Reputation: 362557

What I think you're asking for:

>>> d = {'a': 4, 'b': 7, 'c': 10, 'd': 1} 
>>> a = ['a', 'b', 'd']
>>> sorted(a, key=d.get)
['d', 'a', 'b']

Upvotes: 2

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