How can PHP developers efficiently extract specific information from a string variable, as demonstrated in the forum thread?

To efficiently extract specific information from a string variable in PHP, developers can use functions like `strpos()` and `substr()` to locate and extract the desired data. By identifying unique markers or patterns within the string, developers can pinpoint the information they need and extract it accordingly.

$string = "Hello, my name is John and I am 25 years old.";
$start = strpos($string, "name is ") + strlen("name is ");
$end = strpos($string, " and", $start);
$extracted_info = substr($string, $start, $end - $start);
echo $extracted_info; // Output: John