RegEx：匹配不包含给定单词的字符串

Question

我想检查一个字符串是否不包含字符串，例如：

str1 = "He is a minion, he's so funny."
str2 = "He is not a minion, he's funny."
str3 = "He is not a minion, he's also funny."

我需要检查哪个字符串不包含not和also。因此，预期结果为：str1为false，str2为false，str3为true。

什么是regexp？

Answer 1

您可以使用一系列预测：

(?=.*not)(?=.*also).*

Answer 2

要查找包含多个字词的行，请使用正面预测

(?=.*\bnot\b)(?=.*\balso\b).*

正则表达式：

(?=           look ahead to see if there is:
 .*          any character except \n (0 or more times)
 \b           the boundary between a word char and something that is not a word char
  not         'not'
 \b           the boundary between a word char and something that is not a word char
)             end of look-ahead
(?=           look ahead to see if there is:
 .*          any character except \n (0 or more times)
 \b           the boundary between a word char and something that is not a word char
  also         'also'
 \b           the boundary between a word char and something that is not a word char
)             end of look-ahead
.*            any character except \n (0 or more times)

Live Demo

Answer 3

你也可以不用前瞻来解决这个问题。使用 x 修饰符可以更容易理解正则表达式。

/.*? \b not \b .*? \b also \b | .*? \b also \b .* \b not \b/x