PHP - can't delete mysqli values in the way I want - php

Question

Sorry for the ambiguous title, I don't know how else to name this.
I need to delete specific values in specific quantities from my database. I have a table with some numbers. It looks something like this
1,2(1),3,4,5(6),6(3),7(2),8,9(4),10
The numbers in brackets represent how many times a base number is found in the mysqli database. My form lets me select multiple duplicate numbers and how many duplicates of a number I want to delete. So for example I have selected:
2(1),5(4),9(2)
This is the code that gives me those values but it is imperfect because I receive all the numbers that have at least one duplicate in the database and empty values where there is no number selected and normal numbers when it's selected.
<input type="number" name="quantity[]" id="quantity" min="0" max='<?php echo "$count[$item]"?>' />
input type="hidden" name="hidden[]" id="hidden" value='<?php echo "$item" ?>' />
My thought process is that I needed to build the code so that I knew exactly the number that was selected for the amount of times it is selected. So I wanted to make an associative array from the 2 values that I am supposed to receive. It works, it gives me that information, but I just can't make it delete selected items the number of times that I want, it deletes all the existing duplicates of the selected items.
$arr1 = array();
$arr2 = array();
$newAssoc = array();
if( isset( $_POST['submit'] ) ) {
$quantity = $_POST['quantity'];
$hidden = $_POST['hidden'];
foreach( $hidden as $var1 ) {
$arr1[] = $var1;
}
foreach( $quantity as $var2 ) {
$arr2[] = $var2;
}
$newAssoc = array_combine( $arr1, $arr2 );
foreach( $newAssoc as $key => $val ) {
if( !empty($val)) {
$i = 1;
while( $i <= $val ) {
$delete = mysqli_query( $db, "DELETE FROM duplicates
WHERE numbers=$key" );
++$i;
}
}
}
}
I've tried quite a few things and I'm in a bit of a pickle because nothing worked and I'm out of ideas.
EXPECTED RESULT: I will repeat myself, I need to delete specific values in specific quantities from my database.
Sorry for the wall of text and horrendous code/coding practice/coding logic, still a bit new to both coding and stackoverflow.
Thank you for your help RiggsFolly, your answer has fixed all my problems. If anyone has anything interesting to add I don't mind. Thank you !
This is the portion of the code that was changed in order for my expected result to be fullfiled, if anyone needs it:
foreach( $newAssoc as $key => $val ) {
if( !empty($val)) {
$delete = mysqli_query( $db, "DELETE FROM duplicates
WHERE numbers=$key
LIMIT $val" );
}

Answer 1

On single tables, you can limit the number of rows deleted by using limit.
Your query would look something like DELETE FROM table WHERE key=value LIMIT 10. See the official documentation of mysql.