Notice: Undefined index when trying to increment an associative array in PHP

Question

I'm trying to increment the value for $variable each time a duplicate variable occurs. I'm not sure if this is syntactically correct, but I think this is semantically correct. var_dump seems to spit out the correct outputs, but i get this error: Notice: Undefined index...

$newarray = array();
foreach ($array as $variable)
{
    $newarray[$variable]++; 
    var_dump($newarray);
}

$array = (0 => h, 1 => e, 2 => l, 3=> l, 4=> o);

goal:

'h' => int 1
'e' => int 1
'l' => int 2
'o' => int 1

My code works, it's just that I get some weird NOTICE.

Answer 1

$newarray = array();
foreach ($array as $variable)
{
    if (!isset($newarray[$variable])) {
        $newarray[$variable] = 0;
    }
    $newarray[$variable]++;
}

Answer 2

Take a look at the function array_count_values(). It does exactly what you are trying to do.

Sample from php.net:

$array = array(1, "hello", 1, "world", "hello");
print_r(array_count_values($array));

Result:

Array
(
    [1] => 2
    [hello] => 2
    [world] => 1
)