Javascript:仅替换某些短语中的字母

Question

结束here我被要求用我的评论之一形成一个新问题，所以我来了。我想知道是否可以只替换某些单词中的短语。例如:替换 CBABAC 中的 BAB 但不替换 DABABCC 中的 BAB 谢谢!

Answer 1

使用 lookahead :

BAB(?=AC)

解释

"BAB" +      // Match the characters “BAB” literally
"(?=" +      // Assert that the regex below can be matched, starting at this position (positive lookahead)
   "AC" +       // Match the characters “AC” literally
")"  

或

BAB(?!CC)

解释

"BAB" +      // Match the characters “BAB” literally
"(?!" +      // Assert that it is impossible to match the regex below starting at this position (negative lookahead)
   "CC" +       // Match the characters “CC” literally
")"