Question

我有几个python字符串，我希望删除不需要的字符。

示例：

"This is '-' a test" 
     should be "This is a test"
"This is a test L)[_U_O-Y OH : l’J1.l'}/"
     should be "This is a test"
"> FOO < BAR" 
     should be "FOO BAR"
"I<<W5§!‘1“¢!°\" I" 
     should be "" 
     (because if only words are extracted then it returns I W I and none of them form words)
"l‘?£§l%nbia  ;‘\\~siI.ve_rswinq m"
     should be ""
"2|'J]B"
     should be ""

这是我到目前为止所做的，但它并没有保持单词之间的原始空格。

>>> line = re.sub(r"\W+","","This is '-' a test")
>>> line
'Thisisatest'
>>> line = re.sub(r"\W+","","This is a test L)[_U_O-Y OH : l’J1.l'}/")
>>> line
'ThisisatestL_U_OYOHlJ1l' 
#although i would prefer this to be "This is a test" but if not possible i would 
 prefer "This is a test L_U_OYOHlJ1l"
>>> line = re.sub(r"\W+","","> FOO < BAR")
>>> line
'FOOBAR'
>>> line = re.sub(r"\W+","","I<<W5§!‘1“¢!°\" I")
>>> line
'IW51I'
>>> line = re.sub(r"\W+","","l‘?£§l%nbia  ;‘\\~siI.ve_rswinq m")  
>>> line
'llnbiasiIve_rswinqm'
>>> line = re.sub(r"\W+","","2|'J]B")
>>> line
'2JB'

我将在稍后通过预定义词列表过滤正则表达式清理的单词。

Answer 1

我会选择拆分和过滤器，如下所示：

' '.join(word for word in line.split() if word.isalpha() and word.lower() in list)

这将删除列表中没有的所有非字母单词和字母单词。

示例：

def myfilter(string):
    words = {'this', 'test', 'i', 'a', 'foo', 'bar'}
    return ' '.join(word for word in line.split() if word.isalpha() and word.lower() in words)

>>> myfilter("This is '-' a test")
'This a test'
>>> myfilter("This is a test L)[_U_O-Y OH : l’J1.l'}/")
'This a test'
>>> myfilter("> FOO < BAR")
'FOO BAR'
>>> myfilter("I<<W5§!‘1“¢!°\" I")
'I'
>>> myfilter("l‘?£§l%nbia  ;‘\\~siI.ve_rswinq m")
''
>>> myfilter("2|'J]B")
''

Answer 2

这个清除任何具有至少一个非字母字符的非空格符号组。它会留下一些不需要的字母组：

re.sub(r"\w*[^a-zA-Z ]+\w*","","This is a test L)[_U_O-Y OH : l’J1.l'}/")

给出：

'This is a test  OH  '

它还会留下一组以上的空间：

re.sub(r"[^a-zA-Z ]+\w*","","This is '-' a test")
'This is  a test'  # two spaces

从python字符串中删除字符

2 个答案: