Python Remove Dictionary Item

Sometimes, we may need to remove a specific item from a dictionary to update its structure. For example, consider the dictionary d = {'x': 100, 'y': 200, 'z': 300}. If we want to remove the item associated with the key 'y', several methods can help achieve this. Let’s explore these methods.

Using pop()

pop() method is a straightforward way to remove a dictionary item by specifying its key. If the key exists, it removes the item and returns its value.

# Example
d = {'x': 100, 'y': 200, 'z': 300}
# Remove the item with key 'y'
removed_value = d.pop('y')
print(d)  # Output: {'x': 100, 'z': 300}
print(removed_value)  # Output: 200

{'x': 100, 'z': 300}
200

Explanation:

• pop() removes the item with the specified key and returns its value.
• If the key does not exist, it raises a KeyError unless a default value is provided.

Let's explore some more ways and see how we can remove dictionary item.

Using del()

del() statement allows us to remove a dictionary item by its key. Unlike pop(), it does not return the removed value.

# Example
d = {'x': 100, 'y': 200, 'z': 300}
# Remove the item with key 'y'
del d['y']
print(d)

{'x': 100, 'z': 300}

Explanation:

• The del() statement deletes the item associated with the given key.
• If the key does not exist, it raises a KeyError.

Using Dictionary Comprehension

If we need to remove an item based on its key, we can create a new dictionary that excludes the specified key.

# Example
d = {'x': 100, 'y': 200, 'z': 300}
# Remove the item with key 'y' using dictionary comprehension
d = {k: v for k, v in d.items() if k != 'y'}
print(d)

{'x': 100, 'z': 300}

Explanation:

• A new dictionary is created by including only those key-value pairs where the key is not 'y'.
• This approach does not modify the original dictionary but creates a new one.

Using popitem() (If Last Item)

If the item to be removed is the last one added, popitem() method can be used. It removes and returns the last key-value pair in the dictionary.

# Example
d = {'x': 100, 'y': 200, 'z': 300}
# Remove the last item
removed_item = d.popitem()
print(d) 
print(removed_item) 

{'x': 100, 'y': 200}
('z', 300)

Explanation:

• popitem() removes the last key-value pair from the dictionary.
• This method is only useful if we need to remove the most recently added item in Python 3.7 and later.