A **dictionary** in Python is a collection that is ordered, changeable, and does not allow duplicate keys. It is used to store data values in key-value pairs. Dictionaries are written with curly brackets. An example is given below: 

sample_dict = {
  "type": "Writing",
  "language": "English",
  "year": 2021
}

# 
## Dictionary operations

## 
### Update a dictionary

Python allows a dictionary object to be mutable, meaning update or add operations are permissible. A new item can be pushed or an existing item can be modified with the aid of an assignment operator. 

If an element is added to a key that already exists, its value will be changed to the newly added value. Upon adding a fresh key-value pair, a new item will be added to the existing dictionary.

The different methods to update a dictionary are:

* The assignment method
* The update method 

The example below demonstrates both the addition and update operations on the existing dictionary object. 

my_dict = {'Name': 'Henry', 'Age': 16, 'Subject': 'English'}
print("The student who left is", my_dict.get('Name'))

my_dict['Name'] = 'Perry'
print("The student who replaced him is", my_dict.get('Name'))

my_dict['Name'] = 'Smith'
print("The student who joined is", my_dict.get('Name'))

* The **update method** is an alternative method to modify the value of an existing item. 

sample_dict = {"java" : 1, "python" : 2, "nodejs" : 3}
sample_dict.update( nodejs = 2 )
print(sample_dict)
sample_dict.update( python = 3 )
print(sample_dict)

#  
## Remove items

Several methods are provided by Python to remove items/elements from a dictionary. They include:

## 
##  The `pop()` method:

* This is the most common method to remove items from a dictionary. `pop()` takes a key as an input and deletes the corresponding item/element from the Python dictionary. It returns the value associated with the input key.

## 
##  The `popitem()` method:

* This method removes and returns a random item key-value from the dictionary.

###
### The `clear()` method:

* This method drops all the items from the dictionary. `clear()` is referred to as the `flush` method because it flushes everything from the dictionary.

###
### The `del` method:

* Another way to remove an element from a dictionary is to use the `del` keyword. `del` deletes individual elements and eventually the entire dictionary object.

food_items = {1:"rice", 2:"beans", 3:"yam", 4:"plantain", 5:"potatoes", 6:"wheat"}

# Delete a specific element
print(food_items.pop(6)) 
print(food_items)

# Delete a random element
print(food_items.popitem())
print(food_items)

# Remove a specific element
del food_items[4]
print(food_items)

# Delete all elements from the dictionary
food_items.clear()
print(food_items)

# Eliminates the whole dictionary object
del food_items

> The `clear()` method above removes all the elements from the Python dictionary, leaving it empty. Hence, the subsequent call for the `del` method on the dictionary object removes it altogether. So, adding `print(food_items)` after `del food_items` fails and returns a `NameError`.


How to update and remove elements from a Python dictionary

Python dictionaries store key-value pairs and allow updates and deletions using various methods like pop(), popitem(), clear(), and del.

How to update and remove elements from a Python dictionary

Dictionary operations

Update a dictionary

Remove items

The pop() method:

The popitem() method:

The clear() method:

The del method:

The `pop()` method:

The `popitem()` method:

The `clear()` method:

The `del` method: