Extracting the Minimum x Value Keys from Dictionary

April 13, 2023

Suppose we wish to extract the minimum value from a dictionary like so

scores = {
    0:1.3399288498085087,
    1:1.2672683347433629,
    3:1.6999159970296505, 
    4:1.8410942584597279,
    5:1.336658057628646
}

#find minimum value in dictionary
minimum_value = min(scores.values())

#get keys with minimal value using list comprehension
minimum_keys = [key for key in scores if scores[key]==minimum_value]

minimum_keys

This returns the key with the lowest value. However, what if I wish to extract the minimum 2 keys and put them into a list? What if I wanted the minimum 20? How would I go about doing this for an arbitrary number of minimal values desired?

>Solution :

In fact, the problem is simpler than you think:

scores = {
    0:1.3399288498085087,
    1:1.2672683347433629,
    3:1.6999159970296505, 
    4:1.8410942584597279,
    5:1.336658057628646
}

# minimum key
print(min(scores, key=scores.get))

# n minimum keys
print(sorted(scores, key=scores.get)[:3])

Output:

1
[1, 5, 0]

Both min and sorted allow you to provide a key which is some function to be called with a value, to compute an associated value to be used for sorting. By providing scores.get as that function, you can sort keys by their matching value, which is what you want.