我想在python中删除字符串中的字符:
string.replace(',', '').replace("!", '').replace(":", '').replace(";", '')...
但我有很多字符必须删除。我想了一个清单
list = [',', '!', '.', ';'...]
但是如何使用列表来替换字符串中的字符呢?
我想在python中删除字符串中的字符:
string.replace(',', '').replace("!", '').replace(":", '').replace(";", '')...
但我有很多字符必须删除。我想了一个清单
list = [',', '!', '.', ';'...]
但是如何使用列表来替换字符串中的字符呢?
当前回答
你可以用这样的东西
def replace_all(text, dic):
for i, j in dic.iteritems():
text = text.replace(i, j)
return text
这不是我自己的代码,来自这里,这是一篇伟大的文章,并深入讨论了这样做
其他回答
最近我在钻研scheme,现在我觉得我擅长递归和求值。哈哈哈。分享一些新的方法:
首先,求值
print eval('string%s' % (''.join(['.replace("%s","")'%i for i in replace_list])))
第二,递归
def repn(string,replace_list):
if replace_list==[]:
return string
else:
return repn(string.replace(replace_list.pop(),""),replace_list)
print repn(string,replace_list)
嘿,别投反对票。我只是想分享一些新的想法。
我认为这是足够简单和将做!
list = [",",",","!",";",":"] #the list goes on.....
theString = "dlkaj;lkdjf'adklfaj;lsd'fa'dfj;alkdjf" #is an example string;
newString="" #the unwanted character free string
for i in range(len(TheString)):
if theString[i] in list:
newString += "" #concatenate an empty string.
else:
newString += theString[i]
这是一种方法。但是如果你厌倦了保留一个你想要删除的字符列表,你实际上可以通过使用你迭代的字符串的顺序号来做到这一点。订单号是该字符的ASCII值。0作为字符的ASCII码是48,小写z的ASCII码是122,所以:
theString = "lkdsjf;alkd8a'asdjf;lkaheoialkdjf;ad"
newString = ""
for i in range(len(theString)):
if ord(theString[i]) < 48 or ord(theString[i]) > 122: #ord() => ascii num.
newString += ""
else:
newString += theString[i]
Python 3,单行列表综合实现。
from string import ascii_lowercase # 'abcdefghijklmnopqrstuvwxyz'
def remove_chars(input_string, removable):
return ''.join([_ for _ in input_string if _ not in removable])
print(remove_chars(input_string="Stack Overflow", removable=ascii_lowercase))
>>> 'S O'
如果你使用python2并且输入是字符串(而不是unicode),那么绝对最好的方法是str.translate:
>>> chars_to_remove = ['.', '!', '?']
>>> subj = 'A.B!C?'
>>> subj.translate(None, ''.join(chars_to_remove))
'ABC'
否则,可考虑以下选项:
A.逐字符迭代主题,省略不需要的字符并加入结果列表:
>>> sc = set(chars_to_remove)
>>> ''.join([c for c in subj if c not in sc])
'ABC'
(注意生成器版本“。Join (c for c…)将降低效率)。
B.动态创建正则表达式,re.sub为空字符串:
>>> import re
>>> rx = '[' + re.escape(''.join(chars_to_remove)) + ']'
>>> re.sub(rx, '', subj)
'ABC'
(re.escape确保^或]这样的字符不会破坏正则表达式)。
C.使用translate的映射变体:
>>> chars_to_remove = [u'δ', u'Γ', u'ж']
>>> subj = u'AжBδCΓ'
>>> dd = {ord(c):None for c in chars_to_remove}
>>> subj.translate(dd)
u'ABC'
完整的测试代码和计时:
#coding=utf8
import re
def remove_chars_iter(subj, chars):
sc = set(chars)
return ''.join([c for c in subj if c not in sc])
def remove_chars_re(subj, chars):
return re.sub('[' + re.escape(''.join(chars)) + ']', '', subj)
def remove_chars_re_unicode(subj, chars):
return re.sub(u'(?u)[' + re.escape(''.join(chars)) + ']', '', subj)
def remove_chars_translate_bytes(subj, chars):
return subj.translate(None, ''.join(chars))
def remove_chars_translate_unicode(subj, chars):
d = {ord(c):None for c in chars}
return subj.translate(d)
import timeit, sys
def profile(f):
assert f(subj, chars_to_remove) == test
t = timeit.timeit(lambda: f(subj, chars_to_remove), number=1000)
print ('{0:.3f} {1}'.format(t, f.__name__))
print (sys.version)
PYTHON2 = sys.version_info[0] == 2
print ('\n"plain" string:\n')
chars_to_remove = ['.', '!', '?']
subj = 'A.B!C?' * 1000
test = 'ABC' * 1000
profile(remove_chars_iter)
profile(remove_chars_re)
if PYTHON2:
profile(remove_chars_translate_bytes)
else:
profile(remove_chars_translate_unicode)
print ('\nunicode string:\n')
if PYTHON2:
chars_to_remove = [u'δ', u'Γ', u'ж']
subj = u'AжBδCΓ'
else:
chars_to_remove = ['δ', 'Γ', 'ж']
subj = 'AжBδCΓ'
subj = subj * 1000
test = 'ABC' * 1000
profile(remove_chars_iter)
if PYTHON2:
profile(remove_chars_re_unicode)
else:
profile(remove_chars_re)
profile(remove_chars_translate_unicode)
结果:
2.7.5 (default, Mar 9 2014, 22:15:05)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)]
"plain" string:
0.637 remove_chars_iter
0.649 remove_chars_re
0.010 remove_chars_translate_bytes
unicode string:
0.866 remove_chars_iter
0.680 remove_chars_re_unicode
1.373 remove_chars_translate_unicode
---
3.4.2 (v3.4.2:ab2c023a9432, Oct 5 2014, 20:42:22)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]
"plain" string:
0.512 remove_chars_iter
0.574 remove_chars_re
0.765 remove_chars_translate_unicode
unicode string:
0.817 remove_chars_iter
0.686 remove_chars_re
0.876 remove_chars_translate_unicode
(作为一个边注,remove_chars_translate_bytes的数字可能会给我们一个线索,为什么业界在这么长时间内不愿意采用Unicode)。
删除* % @ !从下面的字符串:
s = "this is my string, and i will * remove * these ** %% "
new_string = s.translate(s.maketrans('','','*%,&@!'))
print(new_string)
# output: this is my string and i will remove these