mysqli_num_rows from class function error - php

Question

This is the first time I learn class in PHP, I tried to make a simple search in database.
here is some script from my class:
class DB {
...
function list_query($query) {
$ns = array();
$q = mysqli_query($this->con_(), $query);
while($n = mysqli_fetch_assoc($q)) {
$ns[] = $n;
}
return $ns;
}
...
function num_query($q) {
$num = mysqli_num_rows($q);
return $num;
}
...
}
search script :
$key = "foo";
$qsearch = $db->list_query("SELECT * FROM posts WHERE content LIKE '%".$db->escape_query($key)."%'");
$num = $db->num_query($qsearch);
if ($num == 0) {
echo "<h2>not found</h2>";
} else {
echo "<h2>result for : ".$key."</h2>";
foreach($qsearch as $val) {
echo "<h4>".$val['title']."</h2>";
echo strip_tags($val['content']);
}
}
but there is an error with the num_query() function.
with warning :
Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, array given in class/db.php on line 30.
I have checked it with manual mysqli_query() then use the num_query() function, it's work well.
sorry for my english

Answer 1

Your list_query() returns array. And your num_query expects mysqli_result as a parameter.
So, when you write $qsearch = $db->list_query(), you're getting an array; and then you pass that array to num_query.
Perhaps, your num_query should be like:
function num_query($result) {
return count($result);
}