How to Update Python Dictionary?

Update Dictionary in Python

You already know that we can access key:value pairs of a Python Dictionary using key as index with the reference to dictionary. In the same way, you can assign a value to this keyed index to dictionary to update the value of key:value pair in this dictionary.

In this tutorial, we will learn how to Update Dictionary in Python.

Updating a Dictionary in Python can be any of the following.

• Update value in key:value pair of Dictionary
• Add new key:value pair to Dictionary
• Delete key:value pair of Dictionary

We will look into each of the above said scenarios using examples.

Update value in key:value pair of Dictionary

To update value in a Dictionary corresponding to a key, all you have to do is assign the value to the key indexed dictionary reference.

In the following program, we update the value in dictionary myDict for key foo.

Python Program

myDict = {
	'foo':12,
	'bar':14
}

#update value for key 'foo'
myDict['foo'] = 56

print(myDict)

Output

{'foo': 56, 'bar': 14}

Add new key:value pair to Dictionary

To add new key:value pair to a Dictionary, you have to assign the value to the key-indexed dictionary reference.

In the following program, we add a new key:value pair 'moo':85 to the dictionary myDict.

Python Program

myDict = {
	'foo':12,
	'bar':14
}

#add key:value to dictionary
myDict['moo'] = 85

print(myDict)

Output

{'foo': 12, 'bar': 14, 'moo': 85}

Delete key:value pair of Dictionary

To delete key:value pair in a Dictionary, you can use del keyword with dictionary[key] as shown in the following program.

Python Program

myDict = {
	'foo':12,
	'bar':14,
	'moo':85
}

#del key:value pair from dictionary
del myDict['foo']

print(myDict)

Output

{'bar': 14, 'moo': 85}

Summary

In this tutorial of Python Examples, we learned how to update Dictionary in Python, with the help of well detailed example programs.