How to change a quote inside a word without changing other quotes in the text

Since the quotation mark is inside the word, there must be letters to its left and right.

Therefore, for the Russian language, the regular may be /([а-яё])"([а-яё])/g .

Substitution pattern: "$ 1 '$ 2" → take the first and second groups (the letters between which there was a quotation mark) and put a single quote between them:

 var text = 'Эту "задачу" "нужн"о сделать" регулярным"и выраже"ниями'; var pattern = /([а-яё])"([а-яё])/g; var result = text.replace(pattern, "$1'$2"); console.log(result); 

A solution that will work in all browsers should not contain a backward preview block. In addition, to replace the quotes, which follow each other through one letter, you cannot do without a preview block ahead .

Therefore, the best solution will be

 var text = 'Эту "задачу" "ну"ж"н"о сделать" регулярным"и выраже"ниями'; var pattern = /([а-яё])"(?=[а-яё])/ig; var result = text.replace(pattern, "$1'"); console.log(result); 

See the regular expression demo .

Details

• ([а-яё]) - Exciting group number 1 (reference to the value of this group from the replacement pattern by using $1 ): the letter of the Russian alphabet
• " - double quote
• (?=[а-яё]) - a block of preview ahead, which checks the following condition: immediately after the sign " must be a letter of the Russian alphabet
• ig - modifiers
  • i - case insensitive enabled
  • g - search for all occurrences enabled

For browsers and environments that support ECMAScript 2018, you can use the following solution for any language:

 var pattern = /(?<=\p{L})"(?=\p{L})/gu; var result = 'Эту "задачу" "ну"ж"н"о сделать" регулярным"и выраже"ниями'.replace(pattern, "'"); console.log(result); 

\p{L} finds any letter.