Loops & Iterations

Loop

• Loop ek block of code ko baar-baar chalata hai.

• Jab tak condition ya items khatam nahi hote, loop repeat hota rehta hai.

• Isse same code baar-baar likhne ki zarurat nahi padti.

• 2 types of loop: For loop and While loop.

Easy AI/ML/DS Example

• Agar Dataset mein 5 student names hain, to Loop har student ka naam ek-ek karke print kar sakta hai.

Python Example

students = ["Ali", "Sara", "Umar"]

for student in students:
    print(student)

Output

Ali
Sara
Umar

Yaad rakhne ki Trick

• Loop = Repeat the same task automatically.

Iterable

• Iterable woh object hota hai jiske items ko ek-ek karke access kiya ja sakta hai.

• e.g: list, tuple, string, set, dictionary

• Iske upar for loop chal sakta hai.

Easy AI/ML/DS Example

• Ek Dataset ke feature names ["Age", "Gender", "Salary"] ek iterable hain. for loop inhe ek-ek karke use kar sakta hai.

Python Example

features = ["Age", "Gender", "Salary"]

for feature in features:
    print(feature)

Output

Age
Gender
Salary

Yaad rakhne ki Trick

• Iterable = Jiski items ko one by one read kar sakte ho.

Iterator

• Iterator ek object hota hai jo iterable ke items ko ek-ek karke deta hai.

• Har baar next item lene ke liye next() use hota hai.

Example of Iterator

• iter(list)

• iter(tuple)

• iter(string)

Easy AI/ML/DS Example

• Agar feature names ["Age", "Gender", "Salary"] hain, to Iterator unhe ek-ek karke process karne mein help karta hai.

Python Example

features = ["Age", "Gender", "Salary"]

it = iter(features)

print(next(it))
print(next(it))
print(next(it))

Output

Age
Gender
Salary

Yaad rakhne ki Trick

• Iterator = Iterable se items one by one nikalne wala object.

For loops

• for loop ka use iterable ke har item par ek-ek karke code chalane ke liye hota hai.

• Jab saare items process ho jaate hain, loop automatically stop ho jaata hai.

Example of for Loop

• list

• tuple

• string

• set

• dictionary

Easy AI/ML/DS Example

• Agar Dataset ke features ["Age", "Gender", "Salary"] hain, to for loop har feature ko ek-ek karke print ya process kar sakta hai.

Python Example

features = ["Age", "Gender", "Salary"]

for feature in features:
    print(feature)

Output

Age
Gender
Salary

Yaad rakhne ki Trick

• for loop = Har item par ek baar code chalao.

While loop

• while loop tab tak code ko baar-baar chalata hai jab tak condition True rehti hai.

• Jaise hi condition False ho jaati hai, loop stop ho jaata hai.

Example of while Loop

• Repeat code until a condition becomes False.

Easy AI/ML/DS Example

• Training ke time, model ko tab tak train karna jab tak epoch < 5 ho.

Python Example

count = 1

while count <= 3:
    print(count)
    count += 1

Output

1
2
3

Yaad rakhne ki Trick

• while loop = Jab tak condition True hai, tab tak repeat karo.