What is a Dictionary ?

               A dictionary in Python is a collection that stores data in the form of key–value pairs. It is declared using curly braces { } .

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" }

Features :

             Key Value pair - Each Value is stored as key value pair

             Key Must be Unique

            Mutable

            Keys must be Immutable

            Unordered


Accessing Dictionary Items :

Using Keys :

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } print(student['name']) #output Ram


get() method :

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } print(student.get("age")) #output 21


keys() method :

                 Returns all the keys

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } print(student.keys()) #output dict_keys(['name', 'age', 'course'])

values() method :

                 Returns all the values

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } print(student.values()) #output dict_values(['Rahul', 21, 'B.Tech'])


items() method :

               Returns the key and values together

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } print(student.items()) #output dict_items([('name', 'Rahul'), ('age', 21), ('course', 'B.Tech')])


Using Loops :

Python 
student = { "name": "Ram", "age": 21, "course": "B.Tech" } for k in student: print(k) #output name age course