Why Am I Getting 'Unknown Modifier 'g' in preg_match' and How Do I Fix It?

Addressing "Unknown Modifier 'g' in preg_match in PHP"

While exploring the intricacies of regular expressions, you may have encountered an error message stating "Unknown modifier 'g' in..." when using preg_match. This issue arises when attempting to utilize the 'g' modifier in your regex pattern. However, there is no 'g' modifier in preg_match.

To resolve this issue, you need to switch to the preg_match_all function instead. Unlike preg_match, which searches for the first occurrence of the pattern and returns a boolean value, preg_match_all searches for all occurrences of the pattern and returns an array of matches.

Correctly Modified Regex Pattern

Your original regex pattern is:

/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/gim

To use this pattern with preg_match_all, modify it as follows:

/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/im

Revised Code

Replace your original preg_match call with the following:

preg_match_all("/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/im", ....)

By making this simple adjustment, you can eliminate the "'g' modifier not supported" error and correctly process multiple occurrences of the pattern in your string.

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