example of build_query function?

build_query() converts an array into a string to be used in an URL. You can pass an array or an object:

$test1 = array (
    'foo'   => 'bar',
    'hello' => 'world'
);
$query1 = build_query( $test1 );
print "<pre>$query1</pre>"; // foo=bar&hello=world

$test2 = array (
    'foo'   => 'bar',
    'hello' => 'world',
    'one'  => array( 1, 2 ),
    'two'  => array(
        'a' => 3,
        'b' => 4
    )
);
$query2 = build_query( $test2 );
print "<pre>$query2</pre>"; // foo=bar&hello=world&deep%5Ba%5D=1&deep%5Bb%5D=2

$test3 = new stdClass;
$test3->foo = 'bar';
$test3->arr = array( 5, 6, 'red' );
$query3 = build_query( $test3 );
print "<pre>$query3</pre>"; // foo=bar&arr%5B0%5D=5&arr%5B1%5D=6&arr%5B2%5D=red

To get the current URL you can use something like this:

$url = set_url_scheme(
        'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']
    );

Now you could use build_query() to append your custom array values to the URL, but you can make that easier with add_query_arg():

$custom = array( 'name' => 'me' );
$url    = add_query_arg( $custom, $url );

add_query_arg() will look for existing parameters in the URL and make sure they don’t get lost or interfere with the $custom values. If there are duplicate entries in both, $custom will overwrite existing parameters.

build_query() is used in add_query_arg() too, but for no obvious reasons you cannot pass an object to add_query_arg() like you can use it in build_query(). Objects are dropped silently.

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