VARIABLES

VARIABLES

 In Python, variables are used to store data values. They serve as named references or placeholders for values that can be used and manipulated within a program. Here's an overview of variables in Python:

Variable Naming:

A variable name can consist of letters (both uppercase and lowercase), digits, and underscores. However, it must start with a letter or an underscore. Python is case-sensitive, so variables named "myVariable" and "myvariable" would be considered different.

Variable Assignment

Variables are created and assigned values using the assignment operator (=). For example:

x = 10 name = "John"

Data Types:

Python is a dynamically typed language, which means you don't need to explicitly declare the type of a variable. The type is automatically inferred based on the assigned value. Common data types in Python include:

• Numeric types: int (integer), float (floating-point number), complex (complex number)
• Strings: str (sequence of characters)
• Boolean: bool (True or False)
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• Collections: list, tuple, set, dictionary
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Variable Reassignment:

Variables can be reassigned with new values of the same or different data types. The type of a variable can change when reassigned to a value of a different type.

Variable Naming Conventions

It's good practice to follow naming conventions to write clean and readable code. Variable names should be descriptive and meaningful. For example, age instead of a, total_students instead of t_s, etc. Python follows the PEP 8 style guide for naming conventions.

Constants:

1. While Python doesn't have built-in support for constants, it is common practice to use uppercase variable names for values that are intended to be treated as constants. Although the value can still be changed, it acts as a convention to indicate that the value should not be modified.

Here's an example showcasing some variable usage in Python:

# Numeric variables x = 5 y = 3.14 # String variables name = "Alice" greeting = "Hello, " + name # Boolean variable is_valid = True # List variable numbers = [1, 2, 3, 4, 5] # Dictionary variable person = {"name": "John", "age": 25} # Variable reassignment x = "Hello" y = 10 # Constants (using uppercase convention) PI = 3.14159 MAX_VALUE = 100

Remember that variables allow you to store and manipulate data throughout your program, providing a way to store information and refer to it by a name.