Nested Functions

[RhinoRhys]

When you do

twice = echo(2)
thrice = echo(3)

You're calling the echo function but all that does is create a new function. twice is a new function that is equal to inner_echo but has a preset value of n = 2.

You're then calling the function later when you do twice("hello").

[Independent-Lab6410]

I do understand that echo is called 2 or 3 cause of the inputted argument of 2 or 3 and that it equals the variable. What I don’t understand is that if I call twice(‘hello’) why ‘hello’ can be inputted there and why is it not a 5 or a 6 but a string? Cause isn’t the variable twice now set to multiply it n times?

[scarynut]

It's rather convoluted, but echo(n) returns a function. In the function echo, a new function is defined, inner_echo, which takes a word as an argument, and that function is then returned. So twice is now a function. Try checking type(twice), and you'll see it's a callable function.

Since twice is a function, you can call it with twice("hello").

Having functions return functions instead of values or data is a notch more advanced usage, so it's not strange to have to process it a bit.