Lists

List ek ordered, changeable collection hai — shayad Python mein sabse zyada use hone wala data structure. Aap ek hi list mein alag types mix kar sakte ho, lekin practically zyada tar lists ek hi type ki cheezein rakhti hain.

fruits = ["apple", "banana", "cherry"]
print(fruits)
print(fruits[0])
print(fruits[-1])

fruits.append("date")
print(fruits)

fruits.remove("banana")
print(fruits)

print(len(fruits))

['apple', 'banana', 'cherry']
apple
cherry
['apple', 'banana', 'cherry', 'date']
['apple', 'cherry', 'date']
3

• fruits[0] pehla item deta hai, fruits[-1] last item deta hai — negative indexes end se ginte hain
• .append() list ke end mein ek item add karta hai, in place
• .remove() jo pehla matching item milta hai use delete kar deta hai
• Lists changeable (mutable) hoti hain — agle lesson mein dikhne wale tuples ke ulat

Sorting

numbers = [5, 3, 1, 4, 2]
numbers.sort()
print(numbers)
numbers.sort(reverse=True)
print(numbers)

[1, 2, 3, 4, 5]
[5, 4, 3, 2, 1]

.sort() list ko in place sort karta hai (original list ko change karta hai aur kuch return nahi karta) — reverse=True order ulta kar deta hai. Agar original ko touch kiye bina sorted copy chahiye to sorted(numbers) use karo.

Aage: tuples — list ka immutable sibling, aur kab actually iska use karna chahiye.