Python – Global Variables

1. What is a Global Variable?

A global variable is a variable that is:

• Created outside a function

• Can be used anywhere in the program

In simple words:
👉 A global variable is available for everyone.

2. Creating a Global Variable

You create a global variable outside any function.

Example

Output:

Here:

• x is created outside the function

• It works inside and outside the function

3. Using Global Variable Inside a Function

A function can read a global variable without any problem.

Example

Output:

4. Changing a Global Variable Inside a Function

To change a global variable inside a function,
you must use the global keyword.

Example

Output:

Without global, Python will give an error.

5. What Happens Without global Keyword?

❌ Wrong Example

Output:

Here:

• x inside function is local

• Global x is not changed

6. Global vs Local Variable (Simple Difference)

Example

Output:

7. When to Use Global Variables?

✔ When value is shared by many functions
✔ When value should stay same everywhere

❌ Avoid too many global variables
They can make code confusing.

8. Common Beginner Mistakes

❌ Forgetting global Keyword

✔ Correct:

9. Simple Practice Examples

Example 1: Global Counter

Example 2: Global Message

10. Summary (Global Variables)

✔ Global variables are created outside functions
✔ Can be used anywhere
✔ Use global to change value inside function
✔ Avoid overuse of global variables

📘 Perfect for Beginner eBook

This chapter is ideal for:

• Python beginner books

• School & college students

• Self-learners

If you want next, I can write:

• Python Local Variables

• Python Functions (easy)

• Python Scope (global vs local)

• Practice questions with answers

Just tell me 😊