python代码优化时间_优化执行时间以检查单词的字符是否在列表python中

我修改了你的功能

chars_array

作为参数,进行了一些速度测试。

def version1(word, chars_array):

chars &＃61;[x for x in word]

count &＃61; 0

for c in chars:

if not c in chars_array:

count&＃43;&＃61;1

return count

def version2(word):

return sum([1 for c in [x for x in word] if not c in chars_array])

我还想测试一个没有中间列表结构和&＃64;tomothy32的函数的修改版本

solution

用

char_array

通过):

def version1a(word, chars_array):

# remove intermediate list construction from word

count &＃61; 0

for c in word:

if not c in chars_array:

count&＃43;&＃61;1

return count

def version3(word, chars_array):

return len(word.translate(None, &＃39;&＃39;.join(chars_array)))

设置定时测试:

# first make some random words

import string

import numpy as np

max_word_len &＃61; 10

N &＃61; 10000

test_words &＃61; [

"".join(

np.random.choice(

list(string.ascii_lowercase),

np.random.randint(1, max_word_len)

)

)

for _ in range(N)

]

定时结果:

chars_array &＃61; [&＃39;a&＃39;,&＃39;b&＃39;,&＃39;c&＃39;]

%%timeit

[version1(word, chars_array) for word in test_words]

#100 loops, best of 3: 11.2 ms per loop

%%timeit

[version1a(word, chars_array) for word in test_words]

#100 loops, best of 3: 8.01 ms per loop

%%timeit

[version2(word, chars_array) for word in test_words]

#100 loops, best of 3: 13.2 ms per loop

%%timeit

[version3(word, chars_array) for word in test_words]

#100 loops, best of 3: 5.29 ms per loop

如此清晰

version3()

使用

str.translate

是这里最快的。但如果我们把

查尔阵

在函数之外。

def version3a(word, chars_array):

return len(word.translate(None, chars_array))

重复正时测试:

chars_array &＃61; "".join(chars_array)

%%timeit

[version1(word, chars_array) for word in test_words]

#100 loops, best of 3: 10.1 ms per loop

%%timeit

[version1a(word, chars_array) for word in test_words]

#100 loops, best of 3: 6.61 ms per loop

%%timeit

[version2(word, chars_array) for word in test_words]

#100 loops, best of 3: 12 ms per loop

%%timeit

[version3(word, chars_array) for word in test_words]

#100 loops, best of 3: 12 ms per loop

%%timeit

[version3a(word, chars_array) for word in test_words]

#100 loops, best of 3: 3.87 ms per loop