I don't understand this code. Somebody help me!

Question

Function as a object.

Answer 1

You have to read the code from inside out:

In the inner parentheses, the function add is called two times for the values 5 and 10.

What's the result of the two calls, what is there after the return?

15+15.

Now for these values, add is called again - the result is 30.

And that is finally returned by do_twice and printed.

Answer 2

That's better! There are two functions in this code. add(x,y) takes two variables (x and y) as parameters and will just return their sum.

So, for a = 5 and b = 10, add(a, b) will return 15.

The function do_twice is a bit tricky. It takes a function name (func) and two variables (x and y) as parameters. Here, we call the function with the parameters add (that's our function), a and b (these are our variables).

If you look at the return statement of do_twice, it looks liks this: func(func(x, y), func(x, y)).

If you replace "func" with the function name that the function receives as a parameter (=add) and x and y with the variables it receives as parameters (=a and b), the return statement actually looks like this:

return add(add(a, b), add(a, b))

or, if you insert the values of a and b:

return add(add(5, 10), add(5, 10))

The next step will be that the expressions within the parentheses are calculated. Both "add(5, 10)" will be replaced by the return value (15):

return add(15, 15)

Now, add() is called again and it adds 15 and 15. Again, add(15, 15) is replaced by the return value:

return 30

There's nothing more to calculate and the function do_twice() will return the value 30.

Answer 3

To be fair, that's not really a code. It's just two words, function and argument

Answer 4

You're welcome. Let's say thank you to HonFu too

Answer 5

thank you HonFu

Answer 6

Whoops. :)

Answer 7

thank you Anna

Answer 8

def add(x, y):
return x + y

def do_twice(func, x, y):
return func(func(x, y), func(x, y))

a = 5
b = 10

print(do_twice(add, a, b))