Python dictionary largest value

Python find max value in a dictionary

In this Python tutorial, we will discuss the Python find max value in a dictionary.

To obtain the maximum value from the dictionary, use the in-built max() function of Python.

Here we will discuss the following 3 methods

Python find max value in a dictionary

In this Python section, we are going to discuss different methods for finding the max value in a dictionary.

Method-1: Using dict.items()

Here we will know how to find the maximum value in a dictionary using the dict.items() method:

# Import the operator module import operator # Create a dictionary with some key-value pairs max_dict = # Use the operator.itemgetter() method in combination with the max() function to find the key with the maximum value new_ma_val = max(max_dict.items(), key=operator.itemgetter(1))[0] # Print the key with the maximum value print((new_ma_val))

In the above code, we first import the operator module, which provides functions for working with operator overloading.

• Then we create a dictionary max_dict with key-value pairs. We use the operator.itemgetter() method in combination with the max() function to find the key with the maximum value.
• The operator.itemgetter() method is used to extract the value from the tuple by using the index passed to it, which is 1 in this case. The max() function compares the values and returns the key-value pair that has the maximum value.
• The key is extracted from the returned tuple by using [0] indexing and is assigned to the variable new_ma_val. Finally, we print the key with the maximum value which is “Japan” with 867 as the max value.

Method-2: Using max() and lambda function

Here we will know how to find the maximum value in a dictionary using the max() and lambda methods:

# Create a dictionary with some key-value pairs Country_dict = # Use the max function with a lambda function to find the key with the maximum value new_val = max(Country_dict, key= lambda x: Country_dict[x]) # Print the key with the maximum value print("maximum value from dictionary:",new_val) 

In the above code, we first create a dictionary Country_dict with key-value pairs.

• Then we use the max() function with a lambda function to find the key with the maximum value. The lambda function takes a single argument x which is the key of the dictionary and returns the value associated with the key.
• The max() function then compares the values and returns the key that has the maximum value. Finally, we print the key with the maximum value, which is ‘China’ with 982 as the max value in this case.

Method-3: Using max() and dict()

Here we will know how to find the maximum value in a dictionary using the max() and dict() methods:

# Create a dictionary with some key-value pairs name_dict = # Extract the values from the dictionary and assign it to a variable new_val = name_dict.values() # Use the max function to find the maximum value maximum_val = max(new_val) # Print the maximum value print("Maximum value from dict:",maximum_val) 

In the above code, we first create a dictionary name_dict with key-value pairs.

• Then we extract the values from the dictionary using the .values() method and assign them to a variable new_val.
• We then use the max() function to find the maximum value from the extracted values. Finally, we print the maximum value which is 56 in this case.

Python find max value in a nested dictionary

In this Python section, we will learn how to find the max value in a dictionary within the dictionary.

# Create a nested dictionary my_dictionary = , 'George' : , 'John' : > # Create a empty dictionary to store the result new_out = <> # Iterate over the outer dictionary keys and values for new_k, new_v in my_dictionary.items(): count_new = 0 # Iterate over the inner dictionary values for element in new_v.values(): # Check if current value is greater than the previous maximum if element > count_new: count_new = element # Assign the maximum value to the outer dictionary key new_out[new_k] = count_new # Print the final dictionary with maximum values print(new_out) 

In the above code, we first create a nested dictionary my_dictionary with multiple keys, each key having its own dictionary as a value.

• We then create an empty dictionary new_out to store the result. We use a for loop to iterate over the outer dictionary keys and values, and another for loop to iterate over the values of the inner dictionary.
• We compare each value of the inner dictionary with a variable count_new, updating the variable if the current value is greater than the previous maximum.
• Then we assign the maximum value to the outer dictionary key by using this key as the key for the new_out dictionary and the maximum value as the value for this key.

Python find max value in a dictionary of lists

In this Python section, we will discuss how to find the max value in a dictionary containing the list.

# Create a dictionary with some key-value pairs dict_new = # Use max() and list comprehension to find the maximum value in the dictionary new_val = max((max(dict_newPython dictionary largest value) for key in dict_new)) # Print the maximum value print(new_val) 

In the above code, we first create a dictionary dict_new with key-value pairs.

• Then we use the max() function and list comprehension to find the maximum value in the dictionary.
• The list comprehension iterates over the keys of the dictionary and for each key, it finds the maximum value in the corresponding list using the max() function.
• Finally, we print the maximum value which is 92 in this case.

You may also like to read the following tutorials on Python dictionary:

In this Python tutorial, we have discussed the Python find max value in a dictionary. Also, we have covered the following methods:

I am Bijay Kumar, a Microsoft MVP in SharePoint. Apart from SharePoint, I started working on Python, Machine learning, and artificial intelligence for the last 5 years. During this time I got expertise in various Python libraries also like Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, etc… for various clients in the United States, Canada, the United Kingdom, Australia, New Zealand, etc. Check out my profile.

Источник

Python: Get Dictionary Key with the Max Value (4 Ways)

In this tutorial, you’ll learn how to use Python to get the dictionary key with max value in a given dictionary, including if multiple keys have the same value. You’ll also learn how to simply get the max value of all keys in a dictionary. You’ll learn how to do this using the operator library, the max() function, and with dictionary comprehensions. You’ll also learn the benefits and the drawbacks of each of these approaches.

The Quick Answer: Use the max() function to get the dictionary key with the max values

What are Python Dictionaries?

Dictionaries in Python are one of the main, built-in data structures. They are collections of items, each consisting of a key:value pairs. Python dictionaries are optimized to retrieve values, when the corresponding dictionary key is known.

Values themselves can be repeated, however keys must be unique. Values can also be of any data type (including other dictionaries), while keys must be immutable data types (such as strings, numbers, or tuples).

Let’s take a look at how dictionaries look in Python. They’re created using <> curly brackets and the key:value pairs are separated by commas.

Let’s create a dictionary called ages , which, well, contains the ages of different people:

We can then access a dictionary item, either by using [] square bracket notation or, better yet, using the .get() dictionary method. Let’s see how we can get the age for Nik :

Now that we’ve covered some of the basics of Python dictionaries, let’s take a look at how we can find the max value of a Python dictionary.

How to Get the Max Value of a Python Dictionary

The simplest way to get the max value of a Python dictionary is to use the max() function. The function allows us to get the maximum value of any iterable.

Let’s see how it works with a list, before diving into a more complex example with a Python dictionary:

some_list = [30, 29, 31, 43, 32, 38] max_value = max(some_list) print(max_value) # Returns: 43

What we can see here, is that we’ve passed in an iterable, a list , and were able to return max value of that iterable.

But how does this work with dictionaries?

Let’s give it a try just by passing in the dictionary:

max_value = max(ages) print(max_value) # Returns: Nik

This isn’t exactly what we’d expected. We were hoping to return 43 , or at least a number!

Python dictionaries come built-in with a .values() method, which extracts the values of our list. If you have a keen eye, you’ll notice that our some_list list contains all the values of our dictionary. We can simply pass in our .values() method into the max function.

max_value = max(ages.values()) print(max_value) # Returns: 43

What we’ve done here is first extracted all the values from our dictionary, and then passed that iterable into our max() function.

Now let’s take a look at how you can return the corresponding key with a max value in Python!

How To Get Dictionary Key with the Max Value in Python

One helpful skill to learn when working with Python dictionaries is how to get the dictionary key that corresponds with the highest value.

The Python max() function actually accepts a parameter to make this much easier: the key= parameter. The way that this parameter works is to define a function that returns a value for each element of the iterable. So, we can simply pass in a function to compare against!

We can use the .get() method we covered earlier to get the max value of a dictionary in Python. You may recall, from the earlier recap of Python dictionaries, that the .get() method is used to return the value for a key. Let’s see what applying this function to our key= parameter does:

ages = < 'Matt': 30, 'Katie': 29, 'Nik': 31, 'Jack': 43, 'Alison': 32, 'Kevin': 38 >max_value = max(ages, key=ages.get) print(max_value) # Jack

We can see here that by passing in key=ages.get that we return the key with the highest value in a Python dictionary.

How to Get Multiple Dictionary Keys with the Max Values in Python

There may be many times when you want to return the key that has the highest value in a Python dictionary. But what if you dictionary has multiple keys that have the highest value?

Unfortunately, the max() function will simply return the first key it finds.

Fortunately, we can find some alternative solutions to this problem!

We can break down our problem as below:

1. Get the max value
2. Create a list comprehension that includes a dictionary key if the key’s value is equal to the max value

Let’s see how we can do this:

ages = < 'Matt': 30, 'Katie': 29, 'Nik': 31, 'Jack': 43, 'Jill': 43, 'Alison': 32, 'Kevin': 38 >max_keys = Python dictionary largest value print(max_keys) # Returns: ['Jack', 'Jill']

In the code above, we loop over the key:value pairs in our dictionary and see if the value is equal to the maximum value. If that’s the case, we add it to our list.

Want to learn more? Check out my in-depth tutorial on Python list comprehensions to learn all you need to know! Or, check out my video on the topic below:

Источник