php count_charsで文字列の各バイトの存在する値を取得する

$result = count_chars(文字列);

<?php

$str = "mebee";

$result = count_chars($str);

print_r($result);

Array
(
    [0] => 0
    [1] => 0
　　.
　　.
　　    
    [97] => 0
    [98] => 1
    [99] => 0
    [100] => 0
    [101] => 3
    [102] => 0
    [103] => 0
    [104] => 0
    [105] => 0
    [106] => 0
    [107] => 0
    [108] => 0
    [109] => 1
　　.
　　.
    [254] => 0
    [255] => 0
)

<?php

$str = "mebee";

$result = count_chars($str);

foreach ($result as $k => $v) {
    if ($result[$k] != 0) echo $k . PHP_EOL;
}

98
101
109

<?php

$str = "mebee";

$result = count_chars($str,1);

print_r($result);

Array
(
    [98] => 1
    [101] => 3
    [109] => 1
)

<?php

$str = "mebee";

$result = count_chars($str,3);

print_r($result);

bem