Python: Least-Recently-Used Cache Demonstration

lru_demo.py

"""Least-Recently-Used Cache Demonstration."""

from functools import lru_cache


@lru_cache(maxsize=5)
def powpow(input: int) -> int:
    output = input**2
    print(f"Computed: {output:3}", end=", ")
    return output


if __name__ == "__main__":
    for i in range(1, 11):
        for j in range(0, 3):
            print(f"(i, j)=({i:2},{j:2})", end=" | ")
            print(f"Cached: {powpow(i):5}")
    for n in range(10, 0, -1):
        for p in range(0, 3):
            print(f"(n, p)=({n:2},{p:2})", end=" | ")
            print(f"Cached: {powpow(n):5}")
    print(powpow.cache_info())

stdout.txt

❯ python .\lru_demo.py
(i, j)=( 1, 0) | Computed:   1, Cached:     1
(i, j)=( 1, 1) | Cached:     1
(i, j)=( 1, 2) | Cached:     1
(i, j)=( 2, 0) | Computed:   4, Cached:     4
(i, j)=( 2, 1) | Cached:     4
(i, j)=( 2, 2) | Cached:     4
(i, j)=( 3, 0) | Computed:   9, Cached:     9
(i, j)=( 3, 1) | Cached:     9
(i, j)=( 3, 2) | Cached:     9
(i, j)=( 4, 0) | Computed:  16, Cached:    16
(i, j)=( 4, 1) | Cached:    16
(i, j)=( 4, 2) | Cached:    16
(i, j)=( 5, 0) | Computed:  25, Cached:    25
(i, j)=( 5, 1) | Cached:    25
(i, j)=( 5, 2) | Cached:    25
(i, j)=( 6, 0) | Computed:  36, Cached:    36
(i, j)=( 6, 1) | Cached:    36
(i, j)=( 6, 2) | Cached:    36
(i, j)=( 7, 0) | Computed:  49, Cached:    49
(i, j)=( 7, 1) | Cached:    49
(i, j)=( 7, 2) | Cached:    49
(i, j)=( 8, 0) | Computed:  64, Cached:    64
(i, j)=( 8, 1) | Cached:    64
(i, j)=( 8, 2) | Cached:    64
(i, j)=( 9, 0) | Computed:  81, Cached:    81
(i, j)=( 9, 1) | Cached:    81
(i, j)=( 9, 2) | Cached:    81
(i, j)=(10, 0) | Computed: 100, Cached:   100
(i, j)=(10, 1) | Cached:   100
(i, j)=(10, 2) | Cached:   100
(n, p)=(10, 0) | Cached:   100
(n, p)=(10, 1) | Cached:   100
(n, p)=(10, 2) | Cached:   100
(n, p)=( 9, 0) | Cached:    81
(n, p)=( 9, 1) | Cached:    81
(n, p)=( 9, 2) | Cached:    81
(n, p)=( 8, 0) | Cached:    64
(n, p)=( 8, 1) | Cached:    64
(n, p)=( 8, 2) | Cached:    64
(n, p)=( 7, 0) | Cached:    49
(n, p)=( 7, 1) | Cached:    49
(n, p)=( 7, 2) | Cached:    49
(n, p)=( 6, 0) | Cached:    36
(n, p)=( 6, 1) | Cached:    36
(n, p)=( 6, 2) | Cached:    36
(n, p)=( 5, 0) | Computed:  25, Cached:    25
(n, p)=( 5, 1) | Cached:    25
(n, p)=( 5, 2) | Cached:    25
(n, p)=( 4, 0) | Computed:  16, Cached:    16
(n, p)=( 4, 1) | Cached:    16
(n, p)=( 4, 2) | Cached:    16
(n, p)=( 3, 0) | Computed:   9, Cached:     9
(n, p)=( 3, 1) | Cached:     9
(n, p)=( 3, 2) | Cached:     9
(n, p)=( 2, 0) | Computed:   4, Cached:     4
(n, p)=( 2, 1) | Cached:     4
(n, p)=( 2, 2) | Cached:     4
(n, p)=( 1, 0) | Computed:   1, Cached:     1
(n, p)=( 1, 1) | Cached:     1
(n, p)=( 1, 2) | Cached:     1
CacheInfo(hits=45, misses=15, maxsize=5, currsize=5)