in_array() keeps appending values if looping through db rows - php

Question

I need to identify every instance where a value in one array (needle) occurs in another array (haystack). in_array() seems to be my best option, and the code below works perfectly until I need to use it on rows fetched from a db - it keeps appending values instead of setting them each time it's called.
While I can't actually use unset() in this situation, I was surprised to discover that even that didn't seem to resolve the problem.
UPDATE - Example of what's being returned
I temporarily changed the db values so that $needles has only value per row (in order to make it possible to sort through the values filling up my screen ;-))
False;
False; False; True;
False; False; True; False; True;
False; False; True; False; True; False; True;
False; False; True; False; True; False; True; False;
This works correctly
(I've posted a functional example here)
$needles = array('John', 'Alex');
$haystack = array('John','Alexander','Kim', 'Michael');
foreach ($needles as $needle) {
if (in_array($needle, $haystack) ) {
$Match = 'True';
}
else {
$Match = 'False';
}
}
This keeps appending values - Edited to reflect the code I'm using
$Customer_Categories_Arr = array('Casual','Trendy');
if ($stmt->columnCount()) {
while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$Product_Categories_Arr[]=$row["Taste_Category"];
// Use when column contains CSV
// $Product_Categories_Arrx = explode(',', trim($Product_Categories_Arr[0]));
foreach ($Product_Categories_Arr as $Product_Category_Arr) {
if (in_array($Product_Category_Arr, $Customer_Categories_Arr)){
$Matches_Product_Category = "True";
} else {
$Matches_Product_Category = "False";
}
echo $Product_Category_Arr, ', ', $Matches_Product_Category, '; ';
}
}
}

Answer 1

It is not really clear what you are trying to do. But maybe this would help:
$customerCategories = array('Casual', 'Trendy');
if( $stmt->columnCount() ){
while( $row = $stmt->fetch( PDO::FETCH_ASSOC )){
$productCategoryRow = $row[ 'Taste_Category' ];
// If it is not working, try uncommenting the next line
// $productCategories = [];
$productCategories = explode( ',', trim( $productCategoryRow ));
$match = "False";
foreach( $productCategories as $productCategory ){
if( in_array( $productCategory, $customerCategories )){
$match = "True";
}
echo $match . ";";
}
}
}
This prints your result on the screen every time a loop is done. Is this what you mean?

Answer 2

If you want the second block of code to do what the first block of code (which works correctly) does, then the second block should look like this -
if ($stmt->columnCount()) {
while($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
$needle =$row["product_var"];
$Match = "False";
if (in_array($needle, $haystack)){
$Match = "True";
}
}
}
You don't need do use the foreach because that is replaced by the while loop in the second block.

Answer 3

I am going to try an solve this. I think the problem is with:
$needles[]=$row["product_var"];
I think this should be:
$needles=$row["product_var"];
The column "product_var" contains an CSV (as you mentioned), so I can make an example like this:
$csv = "jake;john;alex;kim";
An example with brackets ($needles[]):
for($i=0; $i<5; $i++) {
$needles[] = explode(";", $csv);
echo(count($needles).", ");
}
returns:
1, 2, 3, 4, 5,
edit (for more explaining):
if I use print_r I see the array expanding, exactly how it happens in your example:
step 1: it adds an array to $needles with values ('jake','john','alex','kim')
step 2: it adds an array to $needles, so it contains 2x the values ('jake','john','alex','kim')
step 3: it adds an array to $needles, so it contains 3x the values ('jake','john','alex','kim')
etc.
Now without the brackets ($needles):
for($i=0; $i<5; $i++) {
$needles = explode(";", $csv);
echo(count($needles).", ");
}
This returns:
4, 4, 4, 4, 4,
And every time the array simply contains the values ('jake','john','alex','kim') -which is what you want.
Could this explain the "expanding values"? (or am I just doing something really stupid which has nothing to do with your problem??)
edit:
If this is what is going wrong, then you are adding to an array, instead of only using the new array from $row["product_var"] (hope this makes any sense; it seems I am pretty bad at explaining what's happening).