使用Python从字符串中剥离所有非字母数字字符的最佳方法是什么?
在这个问题的PHP变体中提出的解决方案可能会进行一些小的调整,但对我来说似乎不太“python化”。
声明一下,我不只是想去掉句号和逗号(以及其他标点符号),还想去掉引号、括号等。
使用Python从字符串中剥离所有非字母数字字符的最佳方法是什么?
在这个问题的PHP变体中提出的解决方案可能会进行一些小的调整,但对我来说似乎不太“python化”。
声明一下,我不只是想去掉句号和逗号(以及其他标点符号),还想去掉引号、括号等。
当前回答
如果我理解正确,最简单的方法是使用正则表达式,因为它为您提供了很大的灵活性,但另一个简单的方法是使用循环以下是示例代码,我还计算了单词的出现并存储在字典中。
s = """An... essay is, generally, a piece of writing that gives the author's own
argument — but the definition is vague,
overlapping with those of a paper, an article, a pamphlet, and a short story. Essays
have traditionally been
sub-classified as formal and informal. Formal essays are characterized by "serious
purpose, dignity, logical
organization, length," whereas the informal essay is characterized by "the personal
element (self-revelation,
individual tastes and experiences, confidential manner), humor, graceful style,
rambling structure, unconventionality
or novelty of theme," etc.[1]"""
d = {} # creating empty dic
words = s.split() # spliting string and stroing in list
for word in words:
new_word = ''
for c in word:
if c.isalnum(): # checking if indiviual chr is alphanumeric or not
new_word = new_word + c
print(new_word, end=' ')
# if new_word not in d:
# d[new_word] = 1
# else:
# d[new_word] = d[new_word] +1
print(d)
如果这个答案是有用的,请评价这个!
其他回答
for char in my_string:
if not char.isalnum():
my_string = my_string.replace(char,"")
你可以试试:
print ''.join(ch for ch in some_string if ch.isalnum())
作为这里其他一些答案的衍生,我提供了一种非常简单而灵活的方法来定义您想要限制字符串内容的一组字符。在这种情况下,我允许字母数字加破折号和下划线。只需添加或删除字符从我的PERMITTED_CHARS适合您的用例。
PERMITTED_CHARS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-"
someString = "".join(c for c in someString if c in PERMITTED_CHARS)
使用ASCII可打印文件的随机字符串计时:
from inspect import getsource
from random import sample
import re
from string import printable
from timeit import timeit
pattern_single = re.compile(r'[\W]')
pattern_repeat = re.compile(r'[\W]+')
translation_tb = str.maketrans('', '', ''.join(c for c in map(chr, range(256)) if not c.isalnum()))
def generate_test_string(length):
return ''.join(sample(printable, length))
def main():
for i in range(0, 60, 10):
for test in [
lambda: ''.join(c for c in generate_test_string(i) if c.isalnum()),
lambda: ''.join(filter(str.isalnum, generate_test_string(i))),
lambda: re.sub(r'[\W]', '', generate_test_string(i)),
lambda: re.sub(r'[\W]+', '', generate_test_string(i)),
lambda: pattern_single.sub('', generate_test_string(i)),
lambda: pattern_repeat.sub('', generate_test_string(i)),
lambda: generate_test_string(i).translate(translation_tb),
]:
print(timeit(test), i, getsource(test).lstrip(' lambda: ').rstrip(',\n'), sep='\t')
if __name__ == '__main__':
main()
结果(Python 3.7):
Time Length Code
6.3716264850008880 00 ''.join(c for c in generate_test_string(i) if c.isalnum())
5.7285426190064750 00 ''.join(filter(str.isalnum, generate_test_string(i)))
8.1875841680011940 00 re.sub(r'[\W]', '', generate_test_string(i))
8.0002205439959650 00 re.sub(r'[\W]+', '', generate_test_string(i))
5.5290945199958510 00 pattern_single.sub('', generate_test_string(i))
5.4417179649972240 00 pattern_repeat.sub('', generate_test_string(i))
4.6772285089973590 00 generate_test_string(i).translate(translation_tb)
23.574712151996210 10 ''.join(c for c in generate_test_string(i) if c.isalnum())
22.829975890002970 10 ''.join(filter(str.isalnum, generate_test_string(i)))
27.210196289997840 10 re.sub(r'[\W]', '', generate_test_string(i))
27.203713296003116 10 re.sub(r'[\W]+', '', generate_test_string(i))
24.008979928999906 10 pattern_single.sub('', generate_test_string(i))
23.945240008994006 10 pattern_repeat.sub('', generate_test_string(i))
21.830899796994345 10 generate_test_string(i).translate(translation_tb)
38.731336012999236 20 ''.join(c for c in generate_test_string(i) if c.isalnum())
37.942474347000825 20 ''.join(filter(str.isalnum, generate_test_string(i)))
42.169366310001350 20 re.sub(r'[\W]', '', generate_test_string(i))
41.933375883003464 20 re.sub(r'[\W]+', '', generate_test_string(i))
38.899814646996674 20 pattern_single.sub('', generate_test_string(i))
38.636144253003295 20 pattern_repeat.sub('', generate_test_string(i))
36.201238164998360 20 generate_test_string(i).translate(translation_tb)
49.377356811004574 30 ''.join(c for c in generate_test_string(i) if c.isalnum())
48.408927293996385 30 ''.join(filter(str.isalnum, generate_test_string(i)))
53.901889764994850 30 re.sub(r'[\W]', '', generate_test_string(i))
52.130339455994545 30 re.sub(r'[\W]+', '', generate_test_string(i))
50.061149017004940 30 pattern_single.sub('', generate_test_string(i))
49.366573111998150 30 pattern_repeat.sub('', generate_test_string(i))
46.649754120997386 30 generate_test_string(i).translate(translation_tb)
63.107938601999194 40 ''.join(c for c in generate_test_string(i) if c.isalnum())
65.116287978999030 40 ''.join(filter(str.isalnum, generate_test_string(i)))
71.477421126997800 40 re.sub(r'[\W]', '', generate_test_string(i))
66.027950693998720 40 re.sub(r'[\W]+', '', generate_test_string(i))
63.315361931003280 40 pattern_single.sub('', generate_test_string(i))
62.342320287003530 40 pattern_repeat.sub('', generate_test_string(i))
58.249303059004890 40 generate_test_string(i).translate(translation_tb)
73.810345625002810 50 ''.join(c for c in generate_test_string(i) if c.isalnum())
72.593953348005020 50 ''.join(filter(str.isalnum, generate_test_string(i)))
76.048324580995540 50 re.sub(r'[\W]', '', generate_test_string(i))
75.106637657001560 50 re.sub(r'[\W]+', '', generate_test_string(i))
74.681338128997600 50 pattern_single.sub('', generate_test_string(i))
72.430461594005460 50 pattern_repeat.sub('', generate_test_string(i))
69.394243567003290 50 generate_test_string(i).translate(translation_tb)
str.maketrans & str.translate是最快的,但包括所有非ascii字符。 重新编译&模式。Sub较慢,但不知何故比"快。加入&过滤。
如果你想保留像áéíóúãẽĩõũ这样的字符,使用这个:
import re
re.sub('[\W\d_]+', '', your_string)