How to find maximum valued key in dictionary in Python

Question

I am having trouble understanding how the following code finds the key with maximum value in a dictionary. I know first parameter i.e my_dict.keys() returns a list of keys. But I am not getting about 2nd parameter.. Help me out

key_max = max(my_dict.keys(), key=(lambda k: my_dict[k]))

it stores the value returned by lambda function which is my_dict[k] i.e value of the dictionary corresonding to key k — heisenberg, Apr 17 '18 at 06:19

score 0 · Accepted Answer · answered Apr 17 '18 at 06:19

0

So, what that boils down to:

# Your key is what you use to compare
key_value_finder = lambda x: my_dict[x]
test_val = 0
sought_key = None

# All that max is doing is iterating through the list like this
for k in my_dict.keys():

    # Taking the value returned by the `key` param (your lambda)
    tmp_val = key_value_finder(k)

    # And retaining it if the value is higher than the current cache.
    if tmp_val > test_val:
         test_val = tmp_val
         sought_key = k

answered Apr 17 '18 at 06:19

cwallenpoole

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so the actual purpose of 1st parameter my_dict.keys() is to provide key as a paramater to the lambda function for returning the corresponding value and checking for max value repeatedly,is it? – heisenberg Apr 17 '18 at 06:33

score 0 · Answer 2 · answered Apr 17 '18 at 06:21

One more solution to find the key of max value:

d = { 'age1': 10, 'age2': 11}

max_value = max(d.values())
for k, v in d.items():
    if v == max_value:
        print(k)

Explanation:

Find the maximum value using max()

Then using for loop iterate and check for value which is equal to iterating value

for k, v in d.items():
if v == max_value:

How to find maximum valued key in dictionary in Python

2 Answers2