python 自带的内存缓存

痛定思痛。 2021-11-22 08:38 644阅读 0赞

python标准库中的functools模块，提供了functools.lru\_cache，基于内存的缓存。

基于内存缓存  
`lru_cache`

from functools import lru_cache
    
    @lru_cache(maxsize=1)
    def sum2(a,b):
        print(f"计算{a}+{b} ... ")
        return a+b
    
    
    print(sum2(2,3))
    print(sum2(2,3))
    
    print(sum2(4,7))
    print(sum2(4,7))
    
    
    print(sum2(2,3))
    print(sum2(4,7))

maxsize=1，表示可以缓存的元素的个数。
    改变maxsize的值为2，再切换为1，运行程序观察输出结果.
    
    sum2.cache_info()    #查看缓存性能
    sum2.cache_clear()   #清除缓存

--------------------

**基于磁盘的缓存**  
`joblib`

""" 教程 https://joblib.readthedocs.io/en/latest/memory.html 安装 pip install joblib """
    
    from joblib import Memory
    memory = Memory(location="./cachedir")
    
    @memory.cache
    def sum2(a,b):
        print(f"计算{a}+{b} ... ")
        return a+b
    
    
    print(sum2(2,3))
    print(sum2(2,3))
    
    print(sum2(4,7))
    print(sum2(4,7))
    
    
    print(sum2(2,3))
    print(sum2(4,7))

**两个一起用，内存+硬盘缓存**  
**二级缓存 双重缓存**

import time
    import random
    from functools import lru_cache
    from joblib import Memory
    
    memory = Memory(location="cachedir")
    
    @lru_cache(maxsize=5)
    @memory.cache
    def sum2(arg):
        time.sleep(1)
        list1 = [0,1,2]
        a = random.choice(list1)
        arg = 1/a
        return arg
    
    
    if __name__ == "__main__":
        while True:
            for i in ["a1","b2","e3",'d4','e5']:
                arg = i
                t0 = time.time()
                try:
                    res = sum2(arg)
                    print("+++++++++++++++++++++++++++++++++++")
                    print(i,res,"sum2 cost",time.time()-t0)
                    print("+++++++++++++++++++++++++++++++++++")
                except:
                    print("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!")
            input_str = input("继续 or 结束")
            if input_str == 'q':
                break