- preg_match: documentation ( source)
- strrpos: documentation ( source)
<?php
$str = "this is a Test String to get the last index of word with an uppercase letter in PHR";
$pattern = "/.*\s([A-Z])(\w+)/";
//$pattern = "/.*\s([A-Z])([A-Z]+)/"; pattern to match only all caps word
preg_match($pattern, $str, $match);
$letter = $match[1];
$word = $match[1] . $match[2];
$position = strrpos($str, $match[1].$match[2]);
echo "Letter to find: " . $letter . "\nWord to find: " . $word . "\nPosition of letter: " . $position;