Python: If/Else, Functions & Logic Keywords Python: If/Else, Functions & Logic Keywords

01If / Elif / ElseIf / Elif / Else

Teaching the program to make decisions.Program ko decisions lena sikhana.

An if statement checks a condition. If the condition is true, Python runs the indented code below it. If it is not true, Python can run an else block instead.Ek if statement ek condition check karta hai. Agar condition true hai, toh Python uske neeche wala indented code chalata hai. Agar true nahi hai, toh Python uski jagah else block chala sakta hai.

age = 18
if age >= 18:
    print("You are an adult")
else:
    print("You are a minor")

Comparison operatorsComparison operators

These are the symbols we use to compare two values inside a condition:Ye wo symbols hain jinse hum condition mein do values ko compare karte hain:

Adding elif (else-if)elif (else-if) jodna

When there are more than two possibilities, we use elif to check extra conditions, one by one, from top to bottom.Jab do se zyada possibilities hon, toh hum elif use karte hain extra conditions ko ek-ek karke, upar se neeche check karne ke liye.

marks = 75
if marks >= 80:
    print("Grade A")
elif marks >= 60:
    print("Grade B")
else:
    print("Grade C")

Python checks marks >= 80 first (false), then marks >= 60 (true), so it prints Grade B and skips the rest.Python pehle marks >= 80 check karta hai (false), phir marks >= 60 (true), isliye wo Grade B print karta hai aur baaki skip kar deta hai.

02and & notand & not

Joining and flipping conditions.Conditions ko jodna aur palatna.

and — both must be trueand — dono true hone chahiye

and joins two conditions. The whole condition is only true when both sides are true.and do conditions ko jodta hai. Poori condition tabhi true hoti hai jab dono taraf true hon.

age = 20
marks = 75
if age >= 18 and marks >= 50:
    print("Welcome! You qualify")

Here age >= 18 is true and marks >= 50 is true, so the message prints. If even one side were false, nothing would print.Yahan age >= 18 true hai aur marks >= 50 bhi true hai, isliye message print hota hai. Agar ek taraf bhi false hoti, toh kuch print nahi hota.

not — reverses a conditionnot — condition ko ulta karta hai

not flips the result: a true condition becomes false, and a false one becomes true.not result ko palat deta hai: true condition false ban jaati hai, aur false condition true ban jaati hai.

age = 15
if not age >= 18:
    print("Sorry, you are not allowed yet")

age >= 18 is false (15 is not 18+). not flips that false into true, so the message runs.age >= 18 false hai (15, 18+ nahi hai). not us false ko true mein palat deta hai, isliye message chalta hai.

03The in keywordin keyword

Checking if something is inside another.Check karna ki kuch kisi ke andar hai ya nahi.

The in keyword checks whether a value exists inside something else — for example, a letter inside a word.in keyword check karta hai ki koi value kisi aur cheez ke andar hai ya nahi — jaise kisi word ke andar koi letter.

name = "Condico"
if "C" in name:
    print("Yes, C is in the name")

It also works to check inside a list (a group of items written in square brackets).Ye list (square brackets mein likhe items ka group) ke andar check karne ke liye bhi kaam karta hai.

fruits = ["apple", "banana", "mango"]
if "banana" in fruits:
    print("We have bananas!")

You can also combine not with in to check that something is not present.Aap not ko in ke saath combine karke ye bhi check kar sakte ho ki kuch maujood nahi hai.

name = "Condico"
if "z" not in name:
    print("There is no z in the name")

04Functions (def)Functions (def)

Reusable blocks of code with a name.Naam wale reusable code ke blocks.

A function is a named block of code that you can run again and again. We create one with the def keyword, and we run it by writing its name followed by ().Ek function code ka ek naam wala block hota hai jise aap baar-baar chala sakte ho. Hum use def keyword se banate hain, aur uske naam ke baad () likhkar use chalate hain.

def greet():
    print("Hello, welcome to Condico!")

greet()

Giving the function some input (parameters)Function ko input dena (parameters)

We can pass values into a function inside the brackets. These are called parameters, and they let the same function behave differently each time.Hum brackets ke andar function mein values bhej sakte hain. Inhe parameters kehte hain, aur ye ek hi function ko har baar alag tarike se kaam karne dete hain.

def greet(name):
    print("Hello", name)

greet("Aman")
greet("Riya")

Getting a value back (return)Value wapas lena (return)

A function can return a result so we can store it or use it later, instead of just printing it.Ek function koi result return kar sakta hai taaki hum use store ya baad mein use kar saken, sirf print karne ke bajaye.

def add(a, b):
    return a + b

result = add(5, 3)
print(result)

05Recap & ChallengeRecap & Challenge

Quick summary, then try it yourself.Chhota summary, phir khud try karo.

🎯 Try these yourself🎯 Ye khud try karo