Understanding Python Variables

What are Variables?

A variable in Python is a reserved memory location that stores values. It acts as a container for data that can be modified during the execution of a program.

Key Concepts

• Naming Variables:
  • Variable names can contain letters, numbers, and underscores.
  • They must start with a letter or an underscore (not a number).
  • Variable names are case-sensitive (e.g., myVar and myvar are considered different).
  • Avoid using Python keywords (such as if, for, while, etc.).

Dynamic Typing:Python is dynamically typed, which means you do not need to declare the type of a variable before assigning a value. The type is determined at runtime based on the assigned value.

python
a = 10        # Integer
a = "Hello"   # Now a string

Assigning Values:Use the assignment operator (=) to assign values to variables.

python
x = 5
name = "Alice"

Types of Variables

Local Variables:Defined within a function, local variables can only be accessed inside that function.

python
def my_function():
    local_var = "I am local!"
    print(local_var)

Global Variables:Defined outside any function, global variables can be accessed anywhere in the program.

python
global_var = "I am global!"

def my_function():
    print(global_var)

Conclusion

Variables are fundamental in Python programming as they allow for the storage and manipulation of data. Understanding how to name, assign, and differentiate between global and local variables is essential for effective coding. By mastering these concepts, beginners can start writing their own Python programs and manage data efficiently.