Python Coding challenge - Day 708| What is the output of the following Python Code?

 Code Explanation:

1) from functools import lru_cache

Imports the lru_cache decorator from the functools module.

lru_cache provides a simple way to memoize function results (cache return values keyed by the function arguments).

2) @lru_cache(maxsize=None)

Applies the decorator to the function f.

maxsize=None means the cache is unbounded (no eviction) — every distinct call is stored forever (until program exit or manual clear).

After this, f is replaced by a wrapper that checks the cache before calling the original function.

3) def f(x):

Defines the (original) function that we want to cache. Important: the wrapper produced by lru_cache controls calling this body.

print("calc", x)

return x * 2

On a cache miss (first time f(3) is called), the wrapper calls this body:

It prints the side-effect calc 3.

It returns x * 2 → 6.

On a cache hit (subsequent calls with the same argument), the wrapper does not execute this body, so the print("calc", x) side-effect will not run again — the cached return value is used instead.

4) print(f(3)) (first call)

The wrapper checks the cache for key (3). Not found → cache miss.

Calls the original f(3):

Prints: calc 3

Returns 6

print(...) then prints the returned value: 6

So the console so far:

calc 3

6

5) print(f(3)) (second call)

The wrapper checks the cache for key (3). Found → cache hit.

It returns the cached value 6 without executing the function body (so no calc 3 is printed this time).

print(...) prints 6.

Final console output (exact order and lines):

calc 3

6

6

✅ Final Output

calc 3

6

6

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