🐍 Python Execution Modes: Interactive vs Script Mode

What is Execution Mode?

Execution Mode refers to the way or the method of processing a Python script. It determines how Python reads and executes your code.

Python offers two ways to run your code:

• 1. Interactive Mode (REPL) — Run Python commands one at a time
• 2. Script Mode — Write and run complete programs stored in files

1. Interactive Mode (REPL)

Interactive Mode is the way of running single lines or blocks of Python code. It's also known as REPL.

REPL stands for Read-Eval-Print-Loop:

• Read: Accepts input from the user and stores it in memory
• Eval: Evaluates the input from memory
• Print: Prints the output from the eval function
• Loop: Creates a loop that terminates when the program ends

Interactive mode provides a simple and quick way to run Python code. You type a command, press Enter, and get immediate results. It's perfect for testing ideas, learning Python basics, and experimenting with small code snippets.

Microsoft Windows [Version 10.0.19045.2604]
(c) Microsoft Corporation. All rights reserved.

C:\Users\HP>python
Python 3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

>>>

Examples in Interactive Mode:

Using the print() function:
>>> print("I am print() and prints something i.e message in interpreted mode.")
I am print() and prints something i.e message in interpreted mode.

Performing mathematical operations:
>>> 1+1
2
>>> 5*5
25
>>> 600-34
566
>>> 56/5
11.2
>>> 56//5
11

Storing values and performing operations:
>>> p="Python"
>>> p*3
'PythonPythonPython'
>>> y="Language"
>>> print("I am not " +p+ " but I am a " +y)
I am not Python but I am a Language

Getting Help in Interactive Mode:

>>> help()

Welcome to Python 3.11's help utility!

If this is your first time using Python, you should definitely check out
the tutorial on the internet at https://docs.python.org/3.11/tutorial/.

Enter the name of any module, keyword, or topic to get help on writing
Python programs and using Python modules.  To quit this help utility and
return to the interpreter, just type "quit".

help> print
Help on built-in function print in module builtins:

print(*args, sep=' ', end='\n', file=None, flush=False)
    ...
    (Type q to exit from help)

2. Script Mode

Script Mode is the execution mode used when you're working with a block of code or more than one line of code. It's used when you want to execute one or more lines of code in one go.

When you want to write a long piece of code, interactive mode is not recommended. Instead, you save your code in a Python file with the .py extension — this file is called a script.

Popular text editors for writing Python scripts include Sublime, Atom, Notepad++, and the built-in IDLE editor. Upon execution, all commands run together.

How to Write and Execute a Python Script:

• From Python IDLE shell, go to File Menu → New File (or Ctrl+N)
• Write your Python script:

print("Welcome to Python")
print("Developed by Guido van Rossum")

• Save the script with a .py extension, e.g., welcome.py
• Execute the script by going to Run Menu → Run Module (or press F5)

Output:
Welcome to Python
Developed by Guido van Rossum

Running Python Scripts from the Command Line:

On Windows:
C:\users\python> python welcome.py
# OR
C:\users\python> welcome.py

Welcome to Python
Developed by Guido van Rossum

On Linux/Unix:
$ chmod +x welcome.py    # Assign execution permissions
$ ./welcome.py           # Run the script

Welcome to Python
Developed by Guido van Rossum

Interactive Mode vs Script Mode

Try It Yourself!

Now it's your turn! Write and run Python code directly in your browser:

Quick Quiz - Test Your Knowledge

Let's see what you've learned about Python execution modes:

Frequently Asked Questions

📚 Where to Go From Here

Now that you understand Python execution modes, here are some related topics to explore: