How to prevent an infinite loop when replacing characters in PHP

During character replacement, there may sometimes be situations where a loop occurs indefinitely. This can be prevented by using the following methods:

1. Limit the number of replacements: When using the str_replace() or preg_replace() functions in PHP to replace characters, you can set a limit on the number of replacements to avoid infinite looping. For example, you can specify the maximum number of replacements in the fourth parameter of the function.
2. Check if the string has changed before and after replacement: After replacing the characters, you can check if the string has changed. If it hasn’t, the replacement operation can be stopped to avoid an endless loop.
3. Limit the replacement scope with regular expressions: When using the preg_replace() function for character replacement, you can use regular expressions to restrict the range of the replacement, avoiding replacing unrelated parts.
4. Replace recursively: When replacing characters, the method of recursively replacing can be used. After each replacement, check the replaced string again until the string no longer changes. This ensures the safety of the replacement.