Global Variables and Constants

The Global Reach program shows how you can read and even change global variables from inside functions.

# Global Reach
# Demonstrates global variables

def read_global():
    print("From inside the local scope of read_global(), value is:", value)

def shadow_global():
    value = -10
    print("From inside the local scope of shadow_global(), value is:", value)
  
def change_global():
    global value
    value = -10
    print("From inside the local scope of change_global(), value is:", value)

# main
# value is a global variable because we're in the global scope here
value = 10
print("In the global scope, value has been set to:", value, "\n")

read_global()
print("Back in the global scope, value is still:", value, "\n")

shadow_global()
print("Back in the global scope, value is still:", value, "\n")

change_global()
print("Back in the global scope, value has now changed to:", value)

input("\n\nPress the enter key to exit.")

What is Reading a Global Variable?

What is Shadowing a Global Variable?

How do we get complete access to a global variable in Python?