How to get just one special character in a string before a letter and insert a comma between them?

Question

I'm trying to insert a comma between a string, like hello)))how are you, I just want to insert it between the ) + letter, I mean, hello))),how are you.

How can I do this using regular expressions and preg_replace?

I have tried using "/(\)+[a-z]){1}/g" but it takes all the ), not just the first one before the letter.

Answer 1

You may use

$result = preg_replace('~\)+\K(?=[a-z])~', ',', $s);

See the regex demo. Case insensitive variation: '~\)+\K(?=[a-z])~i'.

Details

• \)+ - matches 1+ ) chars
• \K - omits the matched ) chars from the match
• (?=[a-z]) - requires a lowercase letter immediately to the right of the current location without adding it to the match value.

Alternative:

$result = preg_replace('~(\)+)([a-z])~', '$1,$2', $s);

See this regex demo. Case insensitive variation: '~(\)+)([a-z])~i'.

Here, (\)+)([a-z]) captures the close parentheses into Group 1 and then the letter is captured into Group 2 and the replacement is the value in Group 1 + , + the value in Group 2.