Functions

Function ek naam wala, dobara istemal ho sakne wala code ka block hai. Jahan bhi aap khud ko milta julta code ek se zyada martaba likhte hue paao, aksar yeh ishara hota hai ke use function bana dena chahiye.

def greet(name):
    return f"Hello, {name}!"

print(greet("Alice"))
print(greet("Bob"))

Hello, Alice!
Hello, Bob!

• def ek function definition shuru karta hai, uske baad uska naam aur parentheses mein parameters aate hain
• return ek value wapas bhejta hai jahan se function call hua tha — iske baghair, function None wapas karta hai
• name ek parameter hai — ek placeholder jo function call karte waqt jo bhi pass karo usse bhar jaata hai

Default arguments

Aap ek parameter ko default value de sakte hain, jisse woh optional ban jaata hai — call karne wale use bilkul chhor bhi sakte hain, ya jab kuch alag chahiye to override kar sakte hain.

def greet(name, greeting="Hello"):
    return f"{greeting}, {name}!"

print(greet("Alice"))
print(greet("Bob", "Hi"))

Hello, Alice!
Hi, Bob!

Aage: lambda functions — chhote, ek line mein likhe hue istemal-aur-phenk functions.