Python dictionary Method - pop()

The pop() method is a built-in dictionary method in Python that removes and returns the value for a given key in the dictionary. The syntax for the pop() method is:

value = my_dict.pop(key[, default])

Here, my_dict is the dictionary to remove the key-value pair from, key is the key to remove, and default is an optional value to return if the key is not found in the dictionary.

If the key is found in the dictionary, the corresponding value is returned and the key-value pair is removed from the dictionary. If the key is not found in the dictionary and a default value is provided, the default value is returned. If the key is not found in the dictionary and no default value is provided, a KeyError is raised.

Here's an example:

# create a dictionary
my_dict = {'apple': 3, 'banana': 2, 'cherry': 5}

# remove the 'banana' key-value pair
value = my_dict.pop('banana')

# print the value and the updated dictionary
print(value)
print(my_dict)

Output:

2
{'apple': 3, 'cherry': 5}

In this example, we create a dictionary my_dict with three key-value pairs. We then use the pop() method to remove the 'banana' key-value pair from the dictionary. The value 2 is returned and stored in the variable value. We then print the value and the updated dictionary.

If we try to remove a key that doesn't exist in the dictionary, a KeyError is raised:

# create a dictionary
my_dict = {'apple': 3, 'banana': 2, 'cherry': 5}

# try to remove a key that doesn't exist
value = my_dict.pop('orange')

Output:

KeyError: 'orange'

To avoid a KeyError, we can provide a default value to return if the key is not found:

# create a dictionary
my_dict = {'apple': 3, 'banana': 2, 'cherry': 5}

# try to remove a key that doesn't exist and provide a default value
value = my_dict.pop('orange', 0)

# print the value and the updated dictionary
print(value)
print(my_dict)

Output:

0
{'apple': 3, 'banana': 2, 'cherry': 5}

In this example, we try to remove the 'orange' key-value pair from the dictionary, but since the key doesn't exist, we provide a default value of 0. The value 0 is returned and stored in the variable value. We then print the value and the updated dictionary.