How to store a value in an array only if unique - php

Question

I'm writing a PHP report which is designed to be exported purely as a CSV file, using commma delimiters.
There are three columns relating to product_id, these three columns are as follows:
SKU Parent / Child Parent SKU
12345 parent 12345
12345_1 child 12345
12345_2 child 12345
12345_3 child 12345
12345_4 child 12345
18099 parent 18099
18099_1 child 18099
At the moment the code looks like this:
<?php
$con_size = array (35,355,36,37,375,38,385,39,395,40,405,41,415,42,425,43,435,44,445,45,455,46,465,47,475,48,485);
$arrlength=count($con_size);
for($x=0;$x<$arrlength;$x++) {
// check if size is available
if($line['quantity_c_size_'.$con_size[$x].'_chain'] > 0 ) {
?>
<? echo 'Shoes'; ?>,
<?=$line['product_id']?>,
,
,
So at the moment this is simply echoing out the product_ID into the SKU column. How would I create an array which tests whether the 'product_id' is unique and if not suffixes the ID with _1, _2, etc.
Thanks,

Answer 1

Test whether it's in the array, and add it if it's not.
if (!in_array($line['product_id'], $SKU)) {
$SKU[] = $line['product_id'];
echo $line['product_id'];
} else {
echo $line['product_id'] . "_1";
}
If you need the suffixes to increment each time, you can do:
$SKU_counters = array();
if (isset($SKU_counters[$line['product_id']])) {
echo $line['product_id'] . "_" . $SKU_counters[$line['product_id']]++;
} else {
echo $line['product_id'];
$SKU_counters[$line['product_id']] = 1;
}
At the end of the loop you do:
$SKU = array_keys($SKU_counters);

Answer 2

Possibly putting most of the work onto the database (not tested):-
<?php
$con_size = array (35,355,36,37,375,38,385,39,395,40,405,41,415,42,425,43,435,44,445,45,455,46,465,47,475,48,485);
$con_check = 'AND (quantity_c_size_'.implode('_chain > 0 OR quantity_c_size_',$con_size).'_chain > 0)';
$sql = "SELECT DISTINCT product_id, #cnt AS out_counter, #cnt:=IF(#prev_product_id=product_id, #cnt + 1, 0), #prev_product_id:=product_id
FROM product
CROSS JOIN (SELECT #prev_product_id:=0, #cnt:=0) sub1
WHERE on_amazon = 'on'
AND active = 'on'
$con_check
ORDER BY product_id";
$result = mysql_query($sql) or die ( mysql_error() );
while ($line = mysql_fetch_assoc($result) )
{
if ($line['out_counter'] == 1)
{
$SKU[] = $line['product_id'];
}
else
{
echo $line['product_id'].'_'.$line['out_counter']." \r\n";
}
}
?>
Takes your list of $con size and builds up a load of WHERE clauses to check each value is greater than 0. This should save you bringing back values which you don't care about.
The SELECT then brings back items in product_id order, but adds a sequence number (which resets to 0 when the product_id is different from the one on the previous row).
Then when looping around the results it saves the value of product_id if the sequence is 1 (ie the first occurrence of that product_id), else it just outputs the product id with the sequence number concatenated onto the end.