Can someone explain this code to me. I was expecting that it will throw error, but the output is 30.

Question

https://code.sololearn.com/caTR7ugblr5F/?ref=app

def x(n):
return lambda y: n + y
F=x(25)
print(F(5))

Answer 1

F = x(25)
Here you are telling Python "Hey Python, when you see F, replace it with a call to function "x" and pass 25 as argument during the call."

So, when you do F(5), Python replaces F with a call to function "x". Then in Python's view

F(5)

Becomes this

x(25)(5)

25 is argument for call to function "x", and 5 is argument for the lambda returned by function "x".

Answer 2

F=x(25)=lambda y:25+y
F(5) =25+5 =30