How can I remove a key from a Python dictionary?

To remove a key from a Python dictionary, you can use one of the following methods:

1. Using del Statement

Syntax:
del dict_name[key]
Removes the key-value pair if the key exists.
Throws KeyError if the key is not found.

my_dict = {'a': 1, 'b': 2, 'c': 3}
del my_dict['b']  # Removes key 'b'
print(my_dict)    # Output: {'a': 1, 'c': 3}

2. Using pop() Method

Syntax:
dict_name.pop(key[, default])
Removes the key and returns its value.

• Returns default if the key does not exist (prevents KeyError).
• Raises KeyError if the key is missing and no default is provided.

my_dict = {'x': 10, 'y': 20}

# Remove 'x' and get its value
value = my_dict.pop('x')
print(value)     # Output: 10
print(my_dict)   # Output: {'y': 20}

# Safe removal with default (no error if key missing)
value = my_dict.pop('z', None)
print(value)     # Output: None (key 'z' not found)

3. Using Dictionary Comprehension

Create a new dictionary excluding the key (original dict remains unchanged):

my_dict = {'a': 1, 'b': 2, 'c': 3}
new_dict = {k: v for k, v in my_dict.items() if k != 'b'}
print(new_dict)  # Output: {'a': 1, 'c': 3}

4. popitem() (Removes Last Inserted Key)

Syntax:
dict_name.popitem()
Removes and returns the last inserted (key, value) pair (Python 3.7+).

my_dict = {'a': 1, 'b': 2, 'c': 3}
item = my_dict.popitem()  # Removes ('c', 3)
print(my_dict)            # Output: {'a': 1, 'b': 2}

Key Differences

Method	Returns Value?	Handles Missing Keys?	Modifies Original Dict?
del dict[key]	❌ No	❌ Raises KeyError	✅ Yes
dict.pop(key)	✅ Yes	❌ Raises KeyError	✅ Yes
dict.pop(key, default)	✅ Yes	✅ Returns default	✅ Yes
Dict Comprehension	❌ No	✅ Safe	❌ Creates new dict

When to Use Which?

• del: When you’re certain the key exists and don’t need the value.
• pop(): When you need the removed value or want to avoid errors for missing keys.
• Dict Comprehension: When you need a new dictionary without altering the original.
• popitem(): When working with ordered dicts and need to remove the last item.

Example Workflow

# Initialize dictionary
data = {'name': 'Alice', 'age': 30, 'city': 'Paris'}

# Remove 'age' and retrieve its value
age = data.pop('age', 'Key not found')
print(f"Removed age: {age}")  # Output: Removed age: 30

# Attempt to remove non-existent key safely
data.pop('country', None)  # No error

# Delete a confirmed existing key
del data['city']
print(data)  # Output: {'name': 'Alice'}