Print Array if Condition Exists - php

Question

I'm working on a printing a baseball team lineup, via php. I want to print a place holder for a missing Player 6 (or any missing position)
So if Player 1 -> Player 5 is OK print, NO Player #6 print place holder, Player 7 -> Player 9 is OK print. I tried to simplify the code. I have tried solving this every which way but I keep getting stuck.
CODE:
$rot = array();
$pos = array();
$jn = array();
$x = 1;
// loads up the arrays from the db
while ( $rot[$x], $pos[$x], $jn[$x])= $r->fetch_row() ) {
$x++;
}
// counts the actual number of players in linuep
// used for validation and error display
$num_players = mysqli_num_rows($r);
// controls the lineup position
for ($i = 1; $i <= 15; $i++){
if($rot[$i] == $i) {
//prints player
$lineup .= "<div data-fp='" . $pos[$i] . "'>" .$jn[$i]. "</div>";
} else {
// prints place holder
$text = "This Position needs to be filled before the next game.";
$lineup .= "<div id='pid' data-rel='".$text."' data-fp='' data-pid='' data-jn='' title=''>x</div>";
}
}
I also tried this to iterate through the array rot[] to find the matching position and print the line but it actually prints the holder repeatedly.
// controls the lineup position
for ($x = 1; $x <= 15; $x++){
for ($i = 1; $i <= ($num_players+1); $i++) {
if ($x == $i) {
//prints player
$lineup .= "<div data-fp='" . $pos[$i] . "'>" .$jn[$i]. "</div>";
} else {
// prints place holder
$text = "This Position needs to be filled before the next game.";
$lineup .= "<div id='pid' data-rel='".$text."' data-fp='' data-pid='' data-jn='' title=''>x</div>";
}
}
}

Answer 1

What about:
# index all players by position while taking them from the database
$players = array();
while ( $row = $r->fetch_row() ) {
list($rot, $pos, $jn) = $row;
$players[$pos] = compact(array('rot', $pos, $jn);
}
...
# line-up players
for ($pos = 1; $pos <= 15; $pos++)
{
$playerExists = isset($players[$pos]);
if ($playerExists)
{
# do this ...
}
else
{
# do that ...
}
}

Answer 2

I think you are creating an array where all numerical elements are filled (i.e. you'll always have a 1 thru 15) and your mistake is in the
if($rot[$i] == $i) {
When populating the arrays from the database, add this line:
$playertoid = array_flip($pos); # pos is the player number array?
i.e.
while ( ($rot[$x], $pos[$x], $jn[$x])= $r->fetch_row() ) {
$x++;
}
$playertoid = array_flip($pos);
Now you've created a reverse lookup table where the index is the player number.
Replace the
if($rot[$i] == $i) {
line with:
if (isset($playertoid[$i])) {