How to get key with maximum value in Python dictionary?

We can find the key with maximum value in a given dictionary using the following ways:

• Using max()
• Using max() with lambda
• Using operator
• Using manual method

Using max():

Syntax:

max(iterable, key, default)

• iterable can be a list, a dictionary, a tuple, etc.
• key performs comparison based on return type of the iterables passed. This is an optional parameter.
• default is the default value to be returned by the max() function in case the iterable is empty.

It returns the maximum value from an iterable.

Example:

dictionary= {'One': 1, 'Two':2, 'Three':3}

max_key = max(dictionary, key=dictionary.get)

print("The key with maximum value is: ",max_key)

Output:

Using operator:

We first import the operator module. The itemgetter() function returns nth index element of an iterable, be it a list, dictionary, tuple, etc., which it takes in as an input. The items() dictionary method gets all the items i.e. key-value pairs from a dictionary and finally, we use the max() function to get the key with maximum value.

Example:

import operator
dictionary= {'One': 1, 'Two':2, 'Three':3}

max_key = max(dictionary.items(), key = operator.itemgetter(1))[0]
print("The key with maximum value is: ",max_key)

Output:

Using lambda with max():

Lambda functions also referred to as anonymous functions, are regular functions defined without a name. We don’t use def to define these functions, instead we use lambda.

Example:

dictionary= {'One': 1, 'Two':2, 'Three':3}

max_key = max(dictionary, key= lamda x: dictionary[x])

print("The key with maximum value is: ",max_key)

Output:

Using manual method:

We define a function named max_key, we get the keys and values of our dictionary using keys() and values() dictionary methods and make them a list using the list() function. We now return an element from the list k whose value v at a particular index has a maximum value using the index() and max() functions.

Example:

dictionary= {'One': 1, 'Two':2, 'Three':3}
def max_key(dictionary):
      v=list(dictionary.values())
      k=list(dictionary.keys())
      return k[v.index(max(v))]

max_key(dictionary)

Output: