$url = "https://southzone.sakura.ne.jp/posted.php";

$data = array(

'vids' => array(0=> "1" , 1=> "2"),

'tids' => array(0=> "10" , 1=> "20")

);

$content = http_build_query($data , '' , '&');

$options = array('http' => array(

'method' => 'POST',

'content' => $content

));

file_get_contents($url , false, stream_context_create($options));

header('HTTP', true, 400);//phpのバージョンで正しく動きません

http_response_code(400);

<?php

$search = "スペースとか無いし";

$keywords = explode(" ", $search);

var_dump($keywords);

結果
array(1) { [0]=> string(27) "スペースとか無いし" }

--

$search = "";

$keywords = explode(" ", $search);

var_dump($keywords);

結果
array(1) { [0]=> string(0) "" }

--

$search = false;

$keywords = explode(" ", $search);

var_dump($keywords);


結果

array(1) { [0]=> string(0) "" }

string(1) "4"

string型だよ！

extension=php_openssl.dll