PHP sort array by key 'value' - php

Question

I have the following code which displays the results that I want. I'm trying to get it to sort on the key 'value' from the output below. So Eric, Eric 2, Eric 3
An example output of $resultnames is:
Array
(
[0] => Array
(
[Eric 2] => Asdf
)
[1] => Array
(
[Eric] => Asdf
)
[2] => Array
(
[Eric 3] => Asdf
)
)
So the key is the first name and the value of that key is the last name. I'm trying to sort the array by first name
foreach (array_chunk($uvugroups, 6, true) as $uvugroup)
{
foreach ($uvugroup as $uvustate) {
echo "<h4>Registrants</h4>";
$fnames = explode( '|', $uvustate['fname'] );
$lnames = explode( '|', $uvustate['lname'] );
$resultnames = array();
foreach ($fnames as $i => $key) {
$resultnames[] = array($key => $lnames[$i]);
}
foreach ($resultnames as $resultname) {
foreach ($resultname as $fkey => $lkey) {
echo "<ul>";
echo "<li>" . $fkey . " " . substr($lkey,0,1) . ".</li>";
echo "</ul>";
}
}
}
}
I tried to use ksort in different places in the code, but it didn't seem to have an effect.

Answer 1

It's a bit hard because the expected output is not defined in the question, but with this code as the contents of the second foreach it should produce a list sorted by first name.
$fnames = explode( '|', $uvustate['fname'] );
$lnames = explode( '|', $uvustate['lname'] );
$resultnames = array_combine($fnames, $lnames);
ksort($resultnames);
echo "<ul>";
foreach ($resultnames as $fkey => $lkey) {
echo "<li>" . $fkey . " " . substr($lkey,0,1) . ".</li>";
}
echo "</ul>";