Python Variables

Variables are essential elements in any programming language, including Python. They serve as containers for storing data values. In Python, variables are dynamically typed, which means that you don't need to declare the variable type explicitly.

Variable Declaration and Assignment

In Python, you can declare a variable and assign a value to it in a single line using the following syntax:

    variable_name = value
  

Here's an example:

    x = 5
  

In the example above, we declared a variable named "x" and assigned the value 5 to it.

Variable Naming Rules

When naming variables in Python, you need to follow certain rules:

• Variable names must start with a letter (a-z, A-Z) or an underscore (_).
• Variable names can only contain letters, numbers, and underscores.
• Variable names are case-sensitive. For example, "myVariable" and "myvariable" are considered different variables.
• Variable names should be descriptive and meaningful to enhance code readability.

Example:

    name = "John"
age = 25
is_student = True
  

In the above example, we declared three variables:

• name: This variable stores the string "John".
• age: This variable stores the integer value 25.
• is_student: This variable stores the boolean value True.

Variable Reassignment

In Python, you can change the value stored in a variable by assigning a new value to it. For example:

    x = 5
x = 10
  

After the above code snippet executes, the variable "x" will hold the value 10 instead of 5.

Using Variables in Expressions

Variables are commonly used in expressions to perform calculations or manipulate data. Here's an example:

    radius = 5
pi = 3.14159
area = pi * radius ** 2
  

In the example above, we calculated the area of a circle using the formula "pi * r^2". The variable "area" stores the result of the calculation.

Conclusion

Python variables are versatile tools for storing and manipulating data. By understanding variable declaration, naming rules, reassignment, and usage in expressions, you can effectively utilize variables to enhance the functionality of your Python programs.