python - 正则表达式有条件地删除括号内的文本

Question

我想知道如何使用正则表达式从 python 中的字符串中删除以下文本。

string = "Hello (John)"
(magic regex)
string = "Hello "

但是，如果括号中的文本包含子字符串“John”，我只想删除它。例如，

string = "Hello (Sally)"
(magic regex)
string = "Hello (Sally)"

这可能吗？谢谢！

Answer 1

import re
REGEX = re.compile(r'\(([^)]+)\)')

def replace(match):
    if 'John' in match.groups()[0]:
        return ''
    return '(' + match.groups()[0] + ')'

my_string = 'Hello (John)'
print REGEX.sub(replace, my_string)
my_string = 'Hello (test John string)'
print REGEX.sub(replace, my_string)
my_string = 'Hello (Sally)'
print REGEX.sub(replace, my_string)

Hello 
Hello 
Hello (Sally)

Answer 2

这应该是您想要的要点：

>>> from re import sub
>>> mystr = "Hello (John)"
>>> sub("(?s)\(.*?John.*?\)", "", mystr)
'Hello '
>>> mystr = "Hello (Sally)"
>>> sub("(?s)\(.*?John.*?\)", "", mystr)
'Hello (Sally)'
>>> mystr = "Hello (John) My John (Sally)"
>>> sub("(?s)\(.*?John.*?\)", "", mystr)
'Hello  My John (Sally)'
>>>

分解：

(?s)   # Dot-all flag to have . match newline characters
\(     # Opening parenthesis
.*?    # Zero or more characters matching non-greedily
John   # Target
.*?    # Zero or more characters matching non-greedily
\)     # Closing parenthesis

Answer 3

如果您只删除 John 的所有实例，您可以执行以下操作：

string = "Hello (John)"
string.replace("(John)", "")
print(string) # Prints "Hello "