Lesson · Hinglish · ⏱ 8 min padhne mein

🔁 Python logic: if/else, loops aur functions

Q: Aapko 1,000 orders pe same discount rule lagaana hai. Kya use karoge?

Loop ke andar function. Rule ko ek baar function mein likho, phir orders pe loop chala kar har ek ke liye call karo.

🏠 Asli zindagi ki misaal

Traffic signal decision leta hai: agar red hai to ruko, warna agar green hai to chalo. Yeh hai if/else. Washing machine ek hi rinse cycle kai baar repeat karti hai. Yeh hai loop. Aur mummy ki chai ki recipe ek baar likhi hui hai aur roz subah reuse hoti hai. Yeh hai function: steps ko ek baar pack karo aur jab chahiye tab call karo.

💡 Aasaan shabdon mein

Programs ko decisions lene padte hain, kaam repeat karna padta hai aur organised rehna padta hai. 'if / elif / else' condition ke hisaab se alag code chalata hai. 'for' loop collection ke har item ke liye code repeat karta hai, aur 'while' loop tab tak repeat karta hai jab tak condition false na ho jaaye. Function ('def' se banta hai) steps ko ek naam ke neeche bundle karta hai, inputs (parameters) leta hai aur 'return' se output deta hai. Achhe functions ek hi clear kaam karte hain, isliye code ko test aur reuse karna aasaan hota hai.

🪜 Step by step

if / elif / else se decisions: if marks >= 90: grade = "A" elif marks >= 75: grade = "B" else: grade = "C". Indentation (4 spaces) batata hai kya block ke andar hai.
for se repeat karo: for city in ["Pune", "Delhi"]: print(city). 5 baar repeat karne ke liye range(5).
Jab tak kuch badle na tab tak while se repeat: while balance < target: balance += saving. Dhyaan rakho loop khatam ho sake.
Logic ko function mein pack karo: def emi(principal, rate, months): ... return value. Code copy karne ke bajaye alag inputs ke saath call karo.
Functions ko chhote known cases se test karo: agar emi(100000, 0, 10) 10000 hona chahiye, to assert se check karo.

🔑 Zaroori shabd

Condition: Aisa sawaal jiska jawaab True/False ho, jaise price > 100.
Loop: Code jo har item ke liye, ya condition badalne tak, repeat hota hai.
Function: Naam wala, reusable code block jismein inputs aur ek output hota hai.

👀 Example dekho

python

def bill(amount):
    if amount >= 500:
        return amount * 0.9   # 10% off on big orders
    return amount

orders = [120, 650, 300]
for o in orders:
    print(o, "→", bill(o))
# 120 → 120, 650 → 585.0, 300 → 300

Kirana store ka discount rule ek baar likha aur har order ke liye use kiya.

⚠️ Aam galtiyaan jinse bachna hai

Galat indentation: tabs aur spaces mix karna ya colon ke baad indent bhoolna errors ya galat logic deta hai.
Infinite while loops: condition kabhi false nahi hoti. Jo variable check kar rahe ho use hamesha update karo.
Function mein return ki jagah print karna. print sirf dikhata hai; return value wapas deta hai taaki doosra code use kar sake.

✅ Jaldi se check karo

Aapko 1,000 orders pe same discount rule lagaana hai. Kya use karoge?

Code 1,000 baar copy-paste karna
Sirf ek if statement
Loop ke andar function

Jawaab dekho

C. Loop ke andar function: Rule ko ek baar function mein likho, phir orders pe loop chala kar har ek ke liye call karo.

🙋 Seekhne wale yeh poochhte hain

for aur while mein kab kaunsa?

for tab jab pata ho kis cheez pe chalna hai (list, range). while tab jab condition badalne tak repeat karna ho aur pata na ho kitni baar.

Function kitna bada hona chahiye?

Itna chhota ki ek sentence mein samjha sako. Agar describe karne mein do baar 'aur' lagana pade, to do functions mein tod do.

📌 Yaad rakho

if = decide karo, loop = repeat karo, function = reuse karo.

Poora course, aapke roadmap ke hisaab se

Progress tracking, quick checks aur step-by-step order ke saath. Yeh lesson in courses ka hissa hai:

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