Python正则表达式，用于查找具有多个变体的字符串的所有匹配项

Question

我很难找到合适的正则表达式模式，它将匹配以下各项的每个变体：

regular expression  
regular-expression  
regular:expression  
regular&expression   

我得到了以下字符串，我需要使用findall()方法来匹配上面列出的每个事件：

str="This is a string to search for a regular expression like regular expression or regular-expression or regular:expression or regular&expression"

Answer 1

import re
str= (
    'This is a string to search for a regular expression '
    'like regular expression or regular-expression or '
    'regular:expression or regular&expression'
)

r = re.compile(r'regular[- &:]expression')
print(r.findall(str))

结果：

['regular expression', 'regular expression',
'regular-expression', 'regular:expression',
'regular&expression']

Answer 2

正确的正则表达式将是' regular -:& expression‘，如下所示

import re
search_string='''This is a string to search for a regular expression like regular 
expression or regular-expression or regular:expression or regular&expression'''

pattern = 'regular[-:&]expression'
match1= re.findall(pattern, search_string)
if match1 != None:
  print(pattern+' matched')
else:
  print(pattern+' did not match')

输出：

 regular[-:&]expression matched 

Answer 3

这是通过以下方式完成的：

import re
search_string='''This is a string to search for a regular expression like regular 
expression or 
regular-expression or regular:expression or regular&expression'''
results1 = re.sub ("regular[ -:&]expression","regular expression", search_string)
print (results1)