Sort Dictionary by Value – Python [With code]

What Is a Dictionary

A dictionary is a collection of key-value pairs in which each key is associated with a single value. Dictionaries are also known as associative arrays, maps, or symbol tables.

In Python, dictionaries are created using curly braces {} and are defined using a list of key-value pairs separated by commas. A colon separates each key-value team :with the key on the left and the value on the right.

Here’s an example of a dictionary in Python:

d = {'apple': 5, 'banana': 2, 'cherry': 7, 'date': 1}

In this example, the dictionary has four key-value pairs: 'apple' is the key and 5 is the value for the first pair, 'banana' is the key and 2 is the value for the second pair, and so on.

You can access the value for a particular key using the indexing operator []. For example, to get the value for the key 'apple', you can use the following code:

value = d['apple']

You can also use the get() method of the dictionary to retrieve the value for a key. This method returns the value for the key if it exists in the dictionary, and returns a default value (which can be specified as a second argument to the get() method) if the key is not found in the dictionary.

For Example:

value = d.get('apple')  # Returns 5
default_value = d.get('orange', 0)  # Returns 0

Sort a dictionary by value

To sort a dictionary by value, you can use the sorted() function, which returns a new sorted list of the dictionary’s keys. Here’s an example:

# Start with a dictionary
d = {'apple': 5, 'banana': 2, 'cherry': 7, 'date': 1}

# Sort the dictionary by value
sorted_keys = sorted(d, key=d.get)

# Print the sorted keys
print(sorted_keys)  # ['date', 'banana', 'apple', 'cherry']

The sorted() the function takes two optional parameters: key and reverse. The key parameter specifies a function that takes an element as input and returns a value used to determine the sort order. In the example above, we used the d.get function as the key, which produces the value for each key in the dictionary. The reverse parameter is a boolean value that specifies whether the list should be sorted in reverse order (True) or not (False, the default).

You can also use the sorted() function to sort a dictionary directly, without first creating a list of keys. Here’s an example:

# Sort the dictionary by value and print the sorted key-value pairs
for key in sorted(d, key=d.get):
  print(key, d[key])

This will print the key-value pairs in the dictionary sorted by value.

You can also use the items() method of the dictionary to get a list of the dictionary’s key-value pairs, and then sort the list using the sorted() function. Here’s an example:

# Get a list of the dictionary's key-value pairs
items = list(d.items())

# Sort the list of key-value pairs
items.sort(key=lambda x: x[1])

# Print the sorted key-value pairs
for key, value in items:
  print(key, value)

Conclusion

To summarize, the sorted() function can be used to sort a dictionary by value by specifying a position as the key parameter that returns the value for each key in the dictionary. You can also use the items() method of the dictionary to get a list of the key-value pairs, and then sort the list using the sorted() function.

In conclusion, the sorted() a function is a valuable tool for sorting dictionaries by value, and there are several different ways to use it to achieve this. It is important to remember that the sorted() function returns a new sorted list of the dictionary’s keys, rather than modifying the dictionary itself, so you may need to create a new dictionary or update the original dictionary with the sorted keys if that is what you want to do.