Python Coding challenge - Day 1292| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Decorator Function

def deco(f):

- The def keyword defines a function named deco.

- The parameter f receives another function as an argument.

- A decorator is a function that modifies or extends the behavior of another function without changing its original code.

2. Defining the Wrapper Function

def wrap(x):

- This defines an inner function named wrap.

- The parameter x receives the argument passed when the decorated function is called.

- The wrapper controls how the original function is executed and how its result is modified.

3. Calling the Original Function

return f(x) + 3

- f(x) calls the original function with the argument x.

- The original function returns a value.

- The expression adds 3 to that returned value.

- The modified result is returned to the caller.

For example, if f(x) returns 8, the wrapper returns 8 + 3 = 11.

4. Returning the Wrapper

return wrap

- The decorator returns the wrap function itself.

- It does not call wrap at this point.

- This replaces the original function reference with the wrapper function.

5. Applying the Decorator

@deco

- The @deco syntax applies the deco decorator to the function defined immediately below it.

- Conceptually, calc is reassigned to deco(calc).

- Therefore, calling calc() invokes the wrapper function.

6. Defining the Original Function

def calc(n):    return n * 2

- The function calc takes a parameter n.

- It multiplies n by 2 and returns the result.

- When n = 4, the original function returns 8.

7. Calling the Decorated Function

print(calc(4))

- The call calc(4) invokes the wrapper because the decorator has been applied.

- The wrapper passes 4 to the original function.

- The original function returns 4 * 2 = 8.

- The wrapper adds 3, producing 8 + 3 = 11.

- Finally, print() displays the returned value.

Final Output

11

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