PHP：检索外部函数时的数组到字符串转换

Good day!

I have a problem here that I can't solve (last 5hrs).

here's my codes:

include 'assets\functionetrieveFunction.php';
$loadGradProgram = array();
$x = count(getCourseInfo());
for($i=0;$i<=$x;$i++){
    $loadGradProgram[$i] = getCourseInfo(); 
}
echo $loadGradProgram[0];

getCourseInfo function

Solution 1:

function getCourseInfo(){
    $getInfo = array();
    include 'assets\database\connect.php';
    $i = 0;
    $x = 0;
    $sql = "SELECT c.courseID, c.courseCode, c.courseTitle, m.description";
    $sql .=" FROM tblcourse as c INNER JOIN tblcoursemajor as m ON c.courseid=m.courseID ORDER BY c.courseID";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $getInfo[$i] = $row;
            $i++;   
        }

        return $getInfo;
    }
}

Result: Array to string conversion

Solution 2:

function getCourseInfo(){
    $getInfo = array();
    $loadInfo = array();
    include 'assets\database\connect.php';
    $i = 0;
    $x = 0;
    $sql = "SELECT c.courseID, c.courseCode, c.courseTitle, m.description";
    $sql .=" FROM tblcourse as c INNER JOIN tblcoursemajor as m ON c.courseid=m.courseID ORDER BY c.courseID";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $getInfo[$i] = $row;
            $i++;   
        }
        $conn->close();

        for($x,$x<=$i;$x++;){
            $loadInfo[] = implode(',', $getInfo[$x]);
        }

        return $loadInfo;
    }
}

Result: Still the same

and this line causing error: echo $loadGradProgram[0];

I use echo just to see if the query is working.

if you want a multi-dimmentional array like in w3c documentation, you do it like this :

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $getInfo[$i][] = $row['courseID'];
        $getInfo[$i][] = $row['courseCode'];
        ...
        $i++;   
    }

    return $getInfo;

then, if you want to diplay an information in the array you can do a foreach loop or a for loop like :

foreach($loadGradProgram as $key => $value) // here the key is useless
{
    echo $value[0];
    echo $value[1];
}

or directly like this :

echo $loadGradProgram[0][0];
echo $loadGradProgram[0][1];
echo $loadGradProgram[1][0];