some examples using substr(),
extracting the first, last, n chars of a string.
reverse a string or see how many times a char is used in a string.

substring examples” makes use of the built-in PHP functions explode( ), count( ), substr( ), strlen( ), array_key_exists( ), ksort( ), join( ), array_reverse( ) and print_r( ).

01 <?php
02 
03 echo '
04 <form method="post" action="./">
05     <input type="text" name="word" />
06     <input type="submit" value="see" />
07 </form>';
08  
09 if(!empty($_POST['word']))
10 {
11     $str = $_POST['word'];
12     
13     $char['original'] = $str;
14     
15     $char['words'] = explode(' ',$str);
16     
17     $char['word_count'] = count($char['words']);
18     
19     $char['first_char'] = substr($str,0,1);
20     
21     $char['last_char'] = substr($str,-1);
22     
23     $char['all_but_first_char'] = substr($str,1);
24     
25     $char['all_but_last_char'] = substr($str,0,-1);
26     
27     $char['char_repeat'] = array();
28     
29     for($x = 0; $x < strlen($str); $x++)
30     {
31         $char['chars'][] = substr($str,$x,1);
32     
33         if(!array_key_exists($str{$x},$char['char_repeat'])) $char['char_repeat'][$str{$x}] = 0;
34     
35         $char['char_repeat'][$str{$x}]++;
36     }
37     
38     $char['char_count'] = strlen($str);
39     
40     ksort($char['char_repeat']);
41     
42     $char['reverse'] = join('',array_reverse($char['chars']));
43     
44     echo '<pre>';
45     print_r($char);
46     echo '</pre>';
47 }
48  
49 ?>