Unable to understand how function is being called in python

Question

How is function (square,cube) being stored in operations variable. How function is being called here? How this code actually executes ?

def square(n):
 return n**2

def cube(n): 
 return n**3
operations = [square, cube]
numbers = [2, 1, 3, 4, 7, 11, 18, 29]
for i, n in enumerate(numbers):
      action = operations[i % 2]
      print(f"{action.__name__}({n}):", action(n))

Output:

square(2): 4
cube(1): 1
square(3): 9
cube(4): 64
square(7): 49
cube(11): 1331
square(18): 324
cube(29): 24389

first of all, please try to make the code more readable by placing it under ``` (code ) ``` format. — Owen Valentinus, Sep 20 '20 at 07:24
Before posting its is readable.i don't know what happens how it changes everytime after posting it — Usus, Sep 20 '20 at 07:28
Pease refer https://stackoverflow.com/questions/34794634/how-to-use-a-variable-as-function-name-in-python — vanisk, Sep 20 '20 at 07:51

score 4 · Accepted Answer · answered Sep 20 '20 at 08:15

4

The first part defines the functions square and cube and stores a reference for each function in the operations list.

def square(n):
 return n**2

def cube(n): 
 return n**3
operations = [square, cube]

The second part enumerates and loops through the numbers, using square when i is even, and cube when it's not.

numbers = [2, 1, 3, 4, 7, 11, 18, 29]
for i, n in enumerate(numbers):
      action = operations[i % 2]
      print(f"{action.__name__}({n}):", action(n))

answered Sep 20 '20 at 08:15

Ahmed Tounsi

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I wanna know that, is n**2 is returned to square which is in the operations list at first. And in the second part of the program, how action(n) prints 4 at first? Could you provide any site links to understand it better? – Usus Sep 20 '20 at 08:45
1

1) action variable has function and has no parameter. 2) i%2 returns 0 for 0,2,4... and 1 for 1,3,5 value of i. 3) This means numbers[0], numbers[2] etc are used for square function, which is operations[0] 4) numbers[1], numbers[3] are used for cube function which is operations[1]. This is the reason, first SQUARE returned then CUBE returned then SQUARE returned then CUBE returned etc., – Abdul Hameed Sep 20 '20 at 09:03

Unable to understand how function is being called in python

1 Answers1