PHP Array from URL param not behaving as expected-CodePudding

I have a URL parameter containing category IDs that I want to treat as an array which looks like this:

http://example.com?cat[]=3,9,13

In PHP I am using this to get the array from the URL parameter:

$catIDs = $_GET['cat'];

When I do an echo gettype($catIDs); it shows that it is in fact being treated as an array, but when I do a print_r($catIDs); I am getting this:

Array ([0] => 3,9,13)

But I am expecting this:

Array ([0] => 3, [1] => 9, [2] => 13)

What am I missing here? Thanks!

CodePudding user response：

The error is not on the server/PHP side, it's on the client/request side. The given URL gives you an array containing one element, a comma-separated string:

cat[]=3,9,13

Yields:

["3,9,13"]

To specify an array via URL parameters, you need to repeat the parameter name for each item:

cat[]=3&cat[]=9&cat[]=13

Yields:

["3","9","13"]

Alternately, you could specify a single parameter that's comma-separated:

cat=3,9,13

And then just split it:

$cat = explode(',', $_GET['cat']);