function getASCIIFrequency($str) {
$frequencyTable = array_fill(0, 128, 0);
for ($i = 0; $i < strlen($str); $i++) {
$frequencyTable[ord($str[$i])]++;
}
$accumulator = [];
foreach ($frequencyTable as $index => $count) {
if ($count > 0) {
$accumulator[chr($index)] = $count;
}
}
return $accumulator;
}
$str = "php javascript c c++ c# java python";
$asciiFrequency = getASCIIFrequency($str);
print_r($asciiFrequency);
/*
run:
Array
(
[ ] => 6
[#] => 1
[+] => 2
[a] => 4
[c] => 4
[h] => 2
[i] => 1
[j] => 2
[n] => 1
[o] => 1
[p] => 4
[r] => 1
[s] => 1
[t] => 2
[v] => 2
[y] => 1
)
*/