Скачать или смотреть Variable, List, Dictionary, Tuple & Reserved Keywords in Python

Seemab Akhtar
SUPER TECH LEARNING
PhNo. -+91-8004651439

Variables:
• What is a variable?: In Python, a variable is a symbolic name that refers to some value or data stored in the computer's memory.
• How to use variables?: To use a variable, you give it a name and assign a value to it using the assignment operator =. For example, age = 30.
• Naming conventions: Variable names should be descriptive and follow certain conventions. They can start with a letter or underscore (_) and can contain letters, numbers, or underscores. Variable names are case-sensitive.
• Dynamic typing: Python is dynamically typed, meaning you don't need to declare the type of a variable explicitly. The interpreter automatically determines the data type based on the value assigned to it.
List:
• What is a list?: A list is a collection of items that are ordered and mutable (modifiable). Lists are created using square brackets [].
• Indexing: Each item in a list is assigned an index, starting from 0 for the first item. You can access elements in a list using their indices.
• Common operations: Lists support various operations such as appending, removing, slicing, and concatenating.
• List comprehension: It's a concise way to create lists based on existing lists, with a more readable and efficient syntax.
Dictionary:
• What is a dictionary?: A dictionary is an unordered collection of key-value pairs. It's similar to a real-world dictionary where you look up words (keys) to find their meanings (values).
• Key-value pairs: Each key in a dictionary must be unique and immutable (such as strings, numbers, or tuples). Values can be of any data type, including lists, dictionaries, or even other tuples.
• Accessing elements: You can access elements in a dictionary using their keys rather than their position.
• Common operations: Dictionaries support operations like adding, updating, and deleting key-value pairs.
Tuple:
• What is a tuple?: A tuple is an ordered, immutable collection of items. Tuples are created using parentheses ().
• Immutability: Once created, the elements of a tuple cannot be changed, added, or removed. However, if an element is mutable (like a list), its internal state can be modified.
• Use cases: Tuples are often used for representing fixed collections of items, such as coordinates, RGB color values, or database records.
• Packing and unpacking: Tuples allow for packing multiple values into a single variable and unpacking them into separate variables.
Understanding these fundamental data structures in Python is crucial as they form the backbone of many programs and algorithms, enabling you to organize and manipulate data efficiently.