php strchr函数的循环操作技巧有哪些

1. 使用while循环来查找字符串中的特定字符

$string = "Hello World"; $char = 'o';  $pos = 0; while (($pos = strpos($string, $char, $pos)) !== false) {     echo "Found $char at position $pos <br>";     $pos++; } 

2. 使用for循环来查找字符串中的特定字符

$string = "Hello World"; $char = 'o';  for ($i = 0; $i < strlen($string); $i++) {     if ($string[$i] == $char) {         echo "Found $char at position $i <br>";     } } 

3. 使用foreach循环来查找字符串中的特定字符

$string = "Hello World"; $char = 'o';  $chars = str_split($string); foreach ($chars as $key => $value) {     if ($value == $char) {         echo "Found $char at position $key <br>";     } }