Python Programming / Python Variables

Global Variables

An introduction to global variables in Python. Learn about global variables, local variables, and the global keyword. This tutorial is part of the Python Variables Course.

2 min readupdated 6 Oct 2026

We can create a variable outside of a function. This is called a global variable. We can access the global variable inside or outside of a function. Let's see an example.

A variable's scope is the region of the program where it is visible. A variable created outside every function lives in the global scope; one created inside a function lives in that function's local scope.

Diagram:

diagram global vs local scope mermaid

  graph TD
    A[Global scope] --> B[name = 'John']
    A --> C[Function display]
    C --> D[Local scope: its own names]
    D -->|can read| B
    D -->|cannot change unless 'global'| B

Where variables are visible

Example:

Python

# Global variable
name = "John"
def display():
    print("Hello, " + name)
display()
print("Hello, " + name)

Output:

cmd

C:\Users\Your Name> python variable.py
Hello, John
Hello, John

In the above example, we created a global variable name outside of the function display(). We can access the global variable name inside or outside of the function display().

Global Keyword

We can create a local variable inside a function. This is called a local variable. We can access the local variable inside the function. We can't access the local variable outside the function. Let's see an example.

Example:

Python

# Global variable
name = "John"
def display():
    # Local variable
    name = "Smith"
    print("Hello, " + name)
display()
print("Hello, " + name)

Output:

cmd

C:\Users\Your Name> python variable.py
Hello, Smith
Hello, John

In this example, we created a local variable name inside the function display(). We can access the local variable name inside the function display(). We can't access the local variable name outside the function display().

We can use the global keyword to access the global variable inside the function. Let's see an example.

Example:

Python

# Global variable
name = "John"
def display():
    # Local variable
    global name
    name = "Smith"
    print("Hello, " + name)
display() 
print("Hello, " + name)

Output:

cmd

C:\Users\Your Name> python variable.py
Hello, Smith
Hello, Smith

In this example, we used the global keyword to access the global variable name inside the function display(). We can access the global variable name inside the function display(). We can also access the global variable name outside the function display().

Use global sparingly. Functions that quietly modify global state are hard to test and debug, because their result depends on data outside the function. Prefer passing values in as parameters and returning results:

Python

# Better than mutating a global
def increment(value):
    return value + 1
 
count = increment(0)   # caller controls the state

Try it: Global Variables Exercises

Exercise 1 – Access Global Variable

exerciseYour turn

script.py

# Task: Exercise 1 – Access Global Variable
# Follow the steps below and fill in the blanks.
# Use the 'Show Solution' button only after you have tried!

# Hint: Use 'def function_name(param1, param2):' to define a function.
# Step: Assign the correct value (a string) to 'name'.
name = ___  # replace ___ with the correct value

# Hint: print(value) displays output; print(a, b) prints multiple values.
def greet():
  # Step: Write the function body here.
  pass  # remove 'pass' and add your code
  # Hint: Access a global variable from inside a function without the global keyword.
  # Step: Call print() with the right argument(s).
  # Example structure: print("Hello,", name)
  print(___)  # replace ___ with the correct expression

# Hint: Run after every change -- small steps are easier to debug!
# Step: Write the required code here.
# greet()
# replace the comment above with working code

# ── Expected Output ──────────────────────────────────────────
# (Run your completed code to check the output)
# ──────────────────────────────────────────────────────────────

Output

Press Run to see what your code prints.

Exercise 2 – Modify Global with global Keyword

exerciseYour turn

script.py

# Task: Exercise 2 – Modify Global with global Keyword
# Follow the steps below and fill in the blanks.
# Use the 'Show Solution' button only after you have tried!

# Hint: Use 'def function_name(param1, param2):' to define a function.
# Step: Assign the correct value (a number) to 'count'.
count = ___  # replace ___ with the correct value

# Hint: print(value) displays output; print(a, b) prints multiple values.
def increment():
  # Step: Write the function body here.
  pass  # remove 'pass' and add your code
  # Hint: Use the global keyword inside the function to modify the global count.
  # Step: Write the required code here.
  # global count
  # replace the comment above with working code
  # Hint: Run after every change -- small steps are easier to debug!
  # Step: Write the required code here.
  # count += 1
  # replace the comment above with working code

# Hint: Read error messages carefully -- they point to the exact line.
# Step: Write the required code here.
# increment()
# replace the comment above with working code
# Step: Write the required code here.
# increment()
# replace the comment above with working code
# Step: Call print() with the right argument(s).
# Example structure: print("Count:", count)
print(___)  # replace ___ with the correct expression

Output

Press Run to see what your code prints.

Exercise 3 – Global vs Local

exerciseYour turn

script.py

# Task: Exercise 3 – Global vs Local
# Follow the steps below and fill in the blanks.
# Use the 'Show Solution' button only after you have tried!

# Hint: Use 'def function_name(param1, param2):' to define a function.
# Step: Assign the correct value (a string) to 'x'.
x = ___  # replace ___ with the correct value

# Hint: print(value) displays output; print(a, b) prints multiple values.
def show():
  # Step: Write the function body here.
  pass  # remove 'pass' and add your code
  # Hint: The local x inside the function does not affect the global x.
  # Step: Assign the correct value (a string) to 'x'.
  x = ___  # replace ___ with the correct value
  # Hint: Run after every change -- small steps are easier to debug!
  # Step: Call print() with the right argument(s).
  # Example structure: print("Inside:", x)
  print(___)  # replace ___ with the correct expression

# Hint: Read error messages carefully -- they point to the exact line.
# Step: Write the required code here.
# show()
# replace the comment above with working code
# Step: Call print() with the right argument(s).
# Example structure: print("Outside:", x)
print(___)  # replace ___ with the correct expression

Output

Press Run to see what your code prints.

Global Variables

Example:

Global Keyword

Example:

Example:

Try it: Global Variables Exercises

Exercise 1 – Access Global Variable

Exercise 2 – Modify Global with global Keyword

Exercise 3 – Global vs Local

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