如何匹配/搜索特定模式但没有另一个特定模式？

Question

我需要匹配一个模式not check一个更大的字符串。

bigger_string = '<some words and> do not check <some other words>'

但在那之后它不应该有一个数字。 所以， not check <some words>应该匹配但not check 67 <some words>不应该匹配。 我试过这些：

re.findall(re.compile(r'not\s*check\s*\D*', re.I), bigger_string)

re.findall(re.compile(r'not\s*check\s*[^0-9]*', re.I), bigger_string)

它不起作用。 这总是返回一个匹配。

Answer 1

\D* in not\s*check\s*\D*表示匹配到第一个数字，如果前面没有数字，则不匹配。

利用

\bnot\s+check\b(?!\s*\d)\D*

见证明。

解释

--------------------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
--------------------------------------------------------------------------------
  not                      'not'
--------------------------------------------------------------------------------
  \s+                      whitespace (\n, \r, \t, \f, and " ") (1 or
                           more times (matching the most amount
                           possible))
--------------------------------------------------------------------------------
  check                    'check'
--------------------------------------------------------------------------------
  \b                       the boundary between a word char (\w) and
                           something that is not a word char
--------------------------------------------------------------------------------
  (?!                      look ahead to see if there is not:
--------------------------------------------------------------------------------
    \s*                      whitespace (\n, \r, \t, \f, and " ") (0
                             or more times (matching the most amount
                             possible))
--------------------------------------------------------------------------------
    \d                       digits (0-9)
--------------------------------------------------------------------------------
  )                        end of look-ahead
--------------------------------------------------------------------------------
  \D*                      non-digits (all but 0-9) (0 or more times
                           (matching the most amount possible))