Magic Methods & CLI Arguments
Magic Methods & CLI Arguments is a core Python concept covering magic Methods & CLI Arguments: Magic methods in Python are the methods This topic is essential for academic learning, board exam preparation, and developing optimized real-world code.
1. Magic Methods (Dunder Methods)
Magic methods in Python are the methods having two underscores prefix and suffix in their name. They are commonly called dunder methods (Double Underscore).
Examples: __init__, __str__, __len__, __add__.
Example: Customizing String Representation
class Book:
def __init__(self, title, author):
self.title = title
self.author = author
def __str__(self):
return f"'{self.title}' by {self.author}"
b = Book("Python Basics", "VD")
print(b) # Uses __str__ to print: 'Python Basics' by VD
2. Command Line Arguments
Sometimes you want to pass information into your script when you run it from the terminal.
Using sys.argv (Simple)
import sys
# Run as: python script.py Vishnu
print(f"Hello, {sys.argv[1]}")
Using argparse (Professional)
import argparse
parser = argparse.ArgumentParser(description="Greet a user.")
parser.add_index("--name", help="The name of the user")
args = parser.parse_args()
print(f"Hello, {args.name}")
Industry Context
Almost all professional backend scripts and CLI tools (like git or mkdocs) use command line arguments to control their behavior.