不同 Python 数据类型的搜寻

Posted 2021-03-21 pypypypy

语言: Python 3.7.2

系统: Win10 Ver. 10.0.17763

主题: 004.01 不同 Python 数据类型的搜寻

最近在作资料搜索比对的案子的时候，发现大量的数据在搜索比对时，速度变的非常慢，慢到完全无法接受，我想要的是 ‘ 立即 ‘ 有结果，结果却是要等好几小时，晕！虽然以 Python 来说，肯定比不上 C 或 Assembly 语言，但是还是要想办法提升一下速度。

以下是在一万笔数据中，找一万笔数据的各种方法以及所需的时间，虽然最后一个方法 index_list_sort(), 速度快了多，但是我还是觉得不够快，而且这里还只是整数的搜索，如果是字符串呢？如果是副字符串呢？各位如果有更好的方法，也请提示，谢谢！

结果:

0:00:04.734338: index_sequence
0:00:01.139984: index_list
0:00:00.330116: index_np
0:00:00.233343: index_np_sort
0:00:00.223401: index_dict
0:00:00.213462: index_set
0:00:00.007977: index_list_sort

代码:

from datetime import datetime
import numpy as np
import bisect
import time
import random
import inspect
import copy

size        =10000
value       = size-1
db          = random.sample(range(size), size)
db_sort     = copy.deepcopy(db)
db_sort.sort()
db_set      =set(db)
db_dict     ={db[i]:i for i inrange(size)}
db_np       = np.array(db)
value       =[i for i inrange(size)]defcall(func):# Call function and calculate execution time, then print duration and function name
    start_time = datetime.now()
    func()print(datetime.now()- start_time,‘:‘,func.__name__)defdo_something():# Do something here, it may get duration different when multi-loop method usedfor i inrange(1000):passdefindex_sequence():# List unsort and just by Python without any method used or built-in function.for i inrange(size):for j inrange(size):if value[j]== db[i]:
                index = j
                do_something()breakdefindex_list():# Unsorted list, use list.index()for i inrange(size):try:
            index = db.index(value[i])except:
            index =-1if index >=0:
            do_something()defindex_np():# By using numpy and np(where)for i inrange(size):
        result = np.where(db_np==value[i])iflen(result[0])!=0:
            do_something()defindex_np_sort():# By using numpy and sorted numpy arrayfor i inrange(size):
        result = np.searchsorted(db_np, value[i])if result != size:
            do_something()defindex_list_sort():# By using bisect libraryfor i inrange(size):
        index = bisect.bisect_left(db, value[i])if index < size-1and value[index]==db[index]:
            do_something()defindex_set():# Set serachfor i inrange(size):if value[i]in db_set:
            do_something()defindex_dict():# Dictionary searchfor i inrange(size):try:
            index = db_dict[value[i]]except:
            index =-1if index >=0:
            do_something()# Test execution time
call(index_sequence)
call(index_list)
call(index_np)
call(index_np_sort)
call(index_dict)
call(index_set)
call(index_list_sort

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最后，感谢观看！