如何通过HTML表单发送PHP数组（使用输入标记）

Question

I would like to send an array in the input form element.

My array:

Array( [0] => 55 [1] => 1 [2] => 4 )

HTML <input> tag:

<input type="hidden" name="category" value="'.$category.'" />

This is the URL my code resulted in:

http://localhost/search?&category%5B%5D=55&category%5B%5D=1&category%5B%5D=4

But I also get this PHP Notice:

PHP Notice: Array to string conversion

How do I send an array via HTML form correctly?

============================

I found this solution:

foreach ($category as $item) {
    echo '<input type="hidden" name="categories[]" value="'.$item.'" />';                       
}

Prepare your array $category. Example:

    echo '<div align="center">  
    <form method="GET" action="/search" />                      
    <input type="hidden" name="search" value="'.$search.'" />'; 

    foreach ($category as $item){

    echo '<input type="hidden" name="categories[]" value="'.$item.'" />'; 

    } 

    echo '<input type="submit">        
    </form>
    </div>';

And get:

if(isset($_GET['categories'])) {

$categories = $_GET['categories'];                    

}