PYTHON PROGRAMMING INDEX

Basics of Python ▾
Python Introduction Python Characteristics Applications of Python First Python Program Advantages and Disadvantages of Python Features of Python Comments in Python Python Indentation Input in Python Output in Python
Python Variables ▾
Variables in Python Naming a Variable in Python Creating Python variable Assiging values to a variable in Python Scope of a variable
Python Programs ▾
Python Prime Number Program Python Program to check if a number is Palindrome
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Scope of a variable

If you've ever tried to use a variable and received a NameError, you've already encountered Variable Scope. The scope of a variable is the specific area in your code where that variable can be accessed or "called." Outside of that area, the variable simply doesn't exist to the program.

  • L (Local): Variables created inside the specific function you are currently in.
  • G (Global): Variables defined at the very top level of your script, outside of any functions.

Local vs. Global (Public vs. Private)

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Think of a global variable like your Instagram DP—everyone can see it. However, the posts inside a private account are Local; only those inside that specific "space" can access them.

  • Global Variable: Created in the main body of the script. Any function within that script can read and use it.
  • Local Variable: Created inside a def function block. it is "private" to that function and disappears once the function finishes running.
Python (Easy Scope) 
# GLOBAL - Out in the open
name = "Logicoria"

def my_function():
    # LOCAL - Hidden inside here
    msg = "Hello"
    print(msg)  # Works: msg is local
    print(name) # Works: name is global

my_function()

# This works (Global access)
print(name)

# This would CRASH (NameError: name 'msg' is not defined)
# print(msg)
Output:
Hello
Logicoria
Logicoria

Questions & Answers:

  • 1. What does the "scope" of a variable define?
    Scope defines the region of a program where a variable is recognized and can be accessed.
  • 2. Where is a global variable defined in a Python script?
    A global variable is defined in the main body of the script, outside of any function blocks.
  • 3. What happens if you try to print a local variable outside its function?
    Python will throw a NameError because the variable does not exist outside the function's scope.
  • 4. When should you use the global keyword inside a function?
    You use it when you want to change the value of a global variable from within the local scope of a function.
  • 5. What is "Variable Shadowing"?
    It occurs when a local variable has the same name as a global variable, causing the function to use the local value and ignore the global one.
  • 6. Which type of variable has a longer lifetime in memory: Local or Global?
    Global variables have a longer lifetime as they stay in memory for the entire duration of the program's execution.