Add/Remove Items

Adding Items:

1. Using Square Brackets:

# You can add a new key-value pair to a dictionary using square brackets []
person = {'name': 'John', 'age': 30}
person['city'] = 'New York'
# Now, person is {'name': 'John', 'age': 30, 'city': 'New York'}

2. Using the update() Method:

# The update() method allows you to add multiple key-value pairs to a dictionary
person = {'name': 'John', 'age': 30}
person.update({'city': 'New York', 'occupation': 'Engineer'})
# Now, person is {'name': 'John', 'age': 30, 'city': 'New York', 'occupation': 'Engineer'}

Removing Items:

1. Using the del Statement:

# You can remove a key-value pair from a dictionary using the del statement
person = {'name': 'John', 'age': 30, 'city': 'New York'}
del person['age']
# Now, person is {'name': 'John', 'city': 'New York'}

# You can also use the del statement to remove the entire dictionary
person = {'name': 'John', 'age': 30, 'city': 'New York'}
del person
# Now, person is not defined anymore

2. Using the pop() Method:

# The pop() method removes a key and returns its associated value. It raises a KeyError if the key is not present
person = {'name': 'John', 'age': 30, 'city': 'New York'}
age = person.pop('age')
# Now, person is {'name': 'John', 'city': 'New York'}, and age contains the removed value (30)

# You can provide a default value to pop() to avoid the KeyError if the key is not present
person = {'name': 'John', 'city': 'New York'}
age = person.pop('age', None)  # Returns None if 'age' is not present

3. Using the popitem() Method:

# The popitem() method removes and returns an arbitrary key-value pair as a tuple. This is useful when you want to remove an item without specifying a particular key
person = {'name': 'John', 'age': 30, 'city': 'New York'}
removed_item = person.popitem()
# Now, person is one item less, and removed_item contains the removed key-value pair

4. Using the clear() Method:

# The clear() method removes all items from the dictionary, leaving it empty
person = {'name': 'John', 'age': 30, 'city': 'New York'}
person.clear()
# Now, person is an empty dictionary: {}

These methods provide a way to modify the content of dictionaries by adding or removing items. Choose the method that best suits your specific use case.