The document explains the features and characteristics of dictionaries in Python, highlighting that they store data in key-value pairs with unique keys and do not allow duplicates. It discusses the structure of a dictionary, data types, and the rules around key immutability and the handling of duplicate keys. Additionally, it provides examples of how to define and manipulate dictionaries.

1. Dictionary
Presented by:
Saliha Mumtaz
Laiba Kalam
Haider Raza
Usman Shafique

2. Introduction:
• Dictionaries are used to store data values in key: value
pairs.
• A dictionary is a collection which is ordered*, changeable
and do not allow duplicates.
• Dictionaries are written with curly brackets, and have keys
and values:

3. Structure:
• thisdict = {
"brand": "Ford",
"model": "Mustang",
"year": 1964
}
print(thisdict)

4. Duplication not allowed
• thisdict = {
"brand": "Ford",
"model": "Mustang",
"year": 1964,
"year": 2020
}
print(thisdict)

5. Dictionary Length
• print(len(thisdict))
• String, int, boolean, and list data types:
• thisdict = {
"brand": "Ford",
"electric": False,
"year": 1964,
"colors": ["red", "white", "blue"]
}

6. FEATURES OF DICTIONARY
IN PYTHON

7. Following are the features of Dictionary
• Keys are unique
dict={1: ‘Apple’, 2: ‘OnePlus’}
• Each key is separated from its value by a colon(:)
dict={1: ‘Apple’, 2: ‘OnePlus’}
• Unordered-The items in dict are stored without any index
value.
• The items are separated by commas,and the whole thing
is enclosed in curly braces.
dict={1: ‘Apple’, 2: ‘OnePlus’}

8. • An empty dictionary without any items is written with just
two curly braces,like this:{}.
dict = {}
• Keys are unique within a dictionary while values may not
be.
dict={1: ‘Apple’, 2: ‘OnePlus’}
item 1 item 2
Key Key
Value Value

9. • keys must be immutable
You can use string,numbers or tuples as dictionary
keys but something like [‘key’] is not allowed.
student={[‘Name’]: ZARA, ‘Age’:7}
print(“student[‘Name’]:”,student[‘Name’])//Type Error
Not Alllowed

10. • More than one entry per key not allowed
It means no duplicate key is allowed.When duplicate
keys encountered during assignment,the last
assignment wins.
student={‘Name’: ‘Zara’, ‘Age’:7, ‘Name’: ‘Manni’}
print(“student[‘Name’]:”,student[‘Name’])
//Output:
student[‘Name’]:Manni

11. Example:

12. Continue…..

13. Output