Lambda Functions

Lambda ek chhota, be-naam function hai jo ek single expression mein define hota hai. Yeh un halaat ke liye hain jahan poora def function likhna zaroorat se zyada hoga kisi aisi cheez ke liye jo aap sirf ek martaba, wahin istemal karoge jahan woh define hui hai.

square = lambda x: x * x
print(square(5))

25

lambda x: x * x ka matlab hai "ek function jo x leta hai aur x * x wapas karta hai" — kaam ke lehaz se def square(x): return x * x likhne jaisa hi hai, bas ek line mein simat gaya. Lambdas mein sirf ek expression ho sakta hai, kai statements nahi.

Lambdas asal mein kahan istemal hote hain

Aap lambdas ko aksar seedha map() (har item ko badlo) aur filter() (sirf condition match karne wale items rakho) jaise functions mein pass hote hue dekhoge, jahan ek alag naam wala function define karna itni chhoti cheez ke liye zaroorat se zyada hoga.

numbers = [1, 2, 3, 4, 5]
squared = list(map(lambda x: x * x, numbers))
print(squared)

evens = list(filter(lambda x: x % 2 == 0, numbers))
print(evens)

[1, 4, 9, 16, 25]
[2, 4]

Aage: list comprehensions — bilkul isi kaam ke liye Python ka zyada mustaqil tareeqa, map() aur filter() ki jagah.