PHP | Remove element from array with reordering?

If you are always removing the first element, then use array_shift() instead of unset().

Otherwise, you should be able to use something like $a = array_values($a).

Another option would be array_splice(). This reorders numeric keys and appears to be a faster method if you are crunching enough data to care. But I like unset() array_values() for readability.

array_splice( $array, $index, $num_elements_to_remove);

http://php.net/manual/en/function.array-splice.php

Speed test:

    ArraySplice process used 7468 ms for its computations
    ArraySplice spent 918 ms in system calls
    UnsetReorder process used 9963 ms for its computations
    UnsetReorder spent 31 ms in system calls

Test Code:

function rutime($ru, $rus, $index) {
    return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
     -  ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
}

function time_output($title, $rustart, $ru) {
        echo $title . " process used " . rutime($ru, $rustart, "utime") .
            " ms for its computations\n";
        echo $title . " spent " . rutime($ru, $rustart, "stime") .
            " ms in system calls\n";
}

$test = array();
for($i = 0; $i<100000; $i++){
        $test[$i] = $i;
}

$rustart = getrusage();
for ($i = 0; $i<1000; $i++){
        array_splice($test,90000,1);
}
$ru = getrusage();
time_output('ArraySplice', $rustart, $ru);

unset($test);
$test = array();
for($i = 0; $i<100000; $i++){
        $test[$i] = $i;
}

$rustart = getrusage();
for ($i = 0; $i<1000; $i++){
        unset($test[90000]);
        $test = array_values($test);
}
$ru = getrusage();
time_output('UnsetReorder', $rustart, $ru);

If you only remove the first item of the array, you could use array_shift($c);

Or reset(); is also a good choice