Lambda Explaination

Asked May 14 '18 at 02:34

Active May 14 '18 at 02:34

Viewed 112 times

I was reading this page and I found the following example code in the Python documentation, but I don't fully understand how the result is produced.

Example:

>>> def make_incrementor(n):
...     return lambda x: x + n
...
>>> f = make_incrementor(42)
>>> f(0)
42
>>> f(1)
43

What I don't fully understand is how the number 42 gets increased to 43 when x isn't set inside the function.

From my understanding every call to f is like calling a new instance of the method, but it doesn't behave that way.

Questions:

Why is the first call to f done like this: f = make_incrementor(42) but the other calls aren't ?
How does x get set so that every number passed to the function as an argument gets added to it?

asked May 14 '18 at 02:34

When you call `f = make_incrementor(42)`, it assigns the following function: `lambda x: x + 42`, to `f` – user3483203 May 14 '18 at 02:38
Because you have a function that returns a function. – Ignacio Vazquez-Abrams May 14 '18 at 02:38
try `f = lambda x: x + 42` and then `f(0)`, `f(1)`. – khachik May 14 '18 at 02:40
https://stackoverflow.com/q/1132941 this is the correct original question here. – Soumendra May 14 '18 at 03:20

0 Answers0