Add multiple value to a query variable in WordPress - php

Question

I am using the below code in functions.php to add custom query variables to my WordPress project.
<?php
function add_custom_query_var( $vars ){
$vars[] = "brand";
return $vars;
}
add_filter( 'query_vars', 'add_custom_query_var' );
?>
And then on the content page I am using:
<?php echo $currentbrand = get_query_var('brand'); ?>
So now I can pass a URL like:
http://myexamplesite.com/store/?brand=nike
and get nike in result.
How can I pass multiple values for a brand. So I would like to have 3 values for brand say, nike, adidas and woodland.
I have tried the following and none of them works:
http://myexamplesite.com/store/?brand=nike&brand=adidas&brand=woodland
It just returns the last brand, in this case woodland.
http://myexamplesite.com/store/?brand=nike+adidas+woodland
This returns all three with spaces. I kind of think this is not the correct solution. So may be there is a correct way to pass multiple values for a query variable and retrieve them in an array may be so that a loop can be run.

Answer 1

Usually you would pass the parameter like ?brand[]=unresponsibleCompany1&brand[]=otherBrandThatDoesNotCareMuch&brand[]=bunchOfCriminals .
In your WordPress PHP code, then get_query_var( 'brand' ) will return you an Array.
Everything else sounds like a relatively cheap but costy workaround.

Answer 2

You will need to pass query parameters in this way;
brand1=nike&brand2=adidas&brand3=woodland
So, different key for each brand
On the page, recieving values
$params = $_GET;
$brands = array();
foreach($params as $k=>$v) {
if(substr($k,0,5)=="brand") {
$brands[] = $v;
}
}
Alternatively
Using your 2nd method
http://myexamplesite.com/store/?brand=nike+adidas+woodland
$brands = explode(" ", $_GET['brand']);
Alternative method looks easier 🙂