- var_dump: documentation ( source)
- array_merge: documentation ( source)
- in_array: documentation ( source)
- arsort: documentation ( source)
- range: documentation ( source)
<?php
$text = <<<TEXT
rkenbgjengrnekjrgn2ioih34fnorfejk
TEXT;
$char = array_merge(range("a", "z"), range("A", "Z"));
$length = strlen($text);
$counter = array();
for($i = 0; $i < $length; $i++) {
$item = $text[$i];
if (in_array($item, $char)) {
$counter[$item] = isset($counter[$item]) ? $counter[$item] + 1 : 1;
}
}
arsort($counter);
var_dump($counter);