Just as we learned with lists, being able to add data to a dictionary is only half the story. A key feature of these mutable data structures is the ability to remove data as well. Whether you’re removing a user’s setting, processing an item from a queue, or resetting a data collection, knowing how to properly delete from a dictionary is essential.
In this post, we’ll cover the three primary methods for removing data from a dictionary: .pop(), .popitem(), and .clear().
.pop(): Removing a Specific Item by Key
The .pop() method is used to remove a specific key-value pair by providing its key. In return, it gives you back the value that was removed, which is useful if you need to use or archive that data.
The syntax is: removed_value = my_dict.pop(key)
user_profile = {"name": "Alice", "age": 30, "city": "New York"}
print(f"Original profile: {user_profile}")
# Pop the 'age' key and store its value
removed_age = user_profile.pop("age")
print(f"Removed age: {removed_age}")
print(f"Profile after pop: {user_profile}")The output will be:
Original profile: {'name': 'Alice', 'age': 30, 'city': 'New York'}
Removed age: 30
Profile after pop: {'name': 'Alice', 'city': 'New York'}Handling Missing Keys
Just like accessing a key with [], trying to .pop() a key that doesn’t exist will raise a KeyError. However, like the .get() method from Post #66, .pop() can accept a second argument: a default value. If the key is not found, this default value is returned instead, and no error is raised.
# 'country' does not exist, so the default value is returned
country = user_profile.pop("country", "Unknown")
print(f"Removed country: {country}")Output: Removed country: Unknown.
.popitem(): Removing the Last Item
The .popitem() method is simpler. It doesn’t take any arguments. It removes and returns the last inserted key-value pair from the dictionary.
This works in a Last-In, First-Out (LIFO) manner, which is reliable because, as we learned in Post #68, dictionaries in modern Python preserve insertion order. The method returns the key and value together as a tuple.
user_profile = {"name": "Alice", "age": 30, "city": "New York"}
print(f"Profile before popitem: {user_profile}")
# Remove the last added item ('city': 'New York')
last_item = user_profile.popitem()
print(f"Removed item (key, value): {last_item}")
print(f"Profile after popitem: {user_profile}")The output shows the key-value pair being removed:
Profile before popitem: {'name': 'Alice', 'age': 30, 'city': 'New York'}
Removed item (key, value): ('city', 'New York')
Profile after popitem: {'name': 'Alice', 'age': 30}.clear(): Removing Everything
Finally, if you want to completely empty a dictionary, removing all of its key-value pairs at once, you can use the .clear() method.
This method modifies the dictionary in-place and returns None.
user_profile = {"name": "Alice", "age": 30, "city": "New York"}
print(f"Profile with data: {user_profile}")
# Empties the dictionary
user_profile.clear()
print(f"Profile after clear: {user_profile}")The output shows the dictionary is now empty:
Profile with data: {'name': 'Alice', 'age': 30, 'city': 'New York'}
Profile after clear: {}What’s Next?
You now have a complete toolkit for removing data from dictionaries. Use .pop() to remove a specific item by key (and get its value back), use .popitem() to remove the last-added item, and use .clear() to empty the entire dictionary.
We’ve learned how to create and manage dictionaries manually. But just like with lists, Python provides a powerful and concise syntax for creating new dictionaries on the fly from existing sequences. In Post #72, we’ll get a glimpse of a more advanced feature: dictionary comprehensions.
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Experienced Cloud & DevOps Engineer with hands-on experience in AWS, GCP, Terraform, Ansible, ELK, Docker, Git, GitLab, Python, PowerShell, Shell, and theoretical knowledge on Azure, Kubernetes & Jenkins. In my free time, I write blogs on ckdbtech.com