Python Dictionary And Its Uses
Dictionary in Python
- Dictionary is a collection of heterogeneous values with key-value pairs.
- Each key in a dictionary must be unique and immutable and values can be mutable.
- Dictionaries are defined using curly braces ‘{}’, with key-value pairs separated by colons ‘:’.
why Key Will be Unique ?
Because Dictionaries are typically implemented using hash tables, which rely on a hash function to compute index of each key-value pair in an underlying array.If keys were not unique, It would be impossible to retrieve data when multiple values associated with same key.
Syntax:
my_dict = {‘apple’:3, ‘banana’:2, ‘orange’:4}
print(my_dict)
Example:
# Dictionary representing information about a person
1.person_info = {
“name”: “Raju”,
“age”: 30,
“languages”: [“Python”, “JavaScript”, “Java”],
}
# Accessing values using keys
print(“Name:”, person_info[“name”])
print(“Age:”, person_info[“age”])
print(“Languages:”,(person_info[“languages”][0])
Output :
Name: Raju
Age: 30
Languages: Python
Real time Examples
Storing User Information in a Web Application: In a web application, you might store user information such as username, email, password, etc., in a dictionary where the keys represent the attributes of the user.
Storing Metadata for Files: Dictionaries can be used to store metadata for files such as file names, sizes, types,and modification dates.
Representing a Database Record: When working with databases, you might represent a database record as a dictionary where keys correspond to column names and values correspond to column values.