获取单选按钮值php

Question

Hi i cant seem to get the value of the radio button generated by the loop statement. The $_POST method doesn't work even there is corresponding radio button name.

 <?php
$servername = "127.0.0.1";
$username = "root";
$password = "";
$dbname = "test";
$i = null;
$conn = new mysqli($servername, $username, $password, $dbname);

for ($t=0;$t<4;$t++){}
$sql = "SELECT * FROM questions LIMIT $t";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    $i = 0; 
        echo  " <form action='radio.php' method='post'><table>";
        echo "<tr>
        <th>Questions</th>
        <th>Answers</th>     </tr> <tr>" ;
    while($row = $result->fetch_assoc()) {
    $ans=array($row['1'],$row['2'],$row['3']);
    shuffle($ans);
    echo $row['question']."<br>";
        foreach ($ans as $choice) {
           echo "<input type='radio' name='radio$i' value = '$choice'>".$choice."<br>";
    } unset($choice);
        echo " </tr>";$i++;
    }


        echo "</table> <input type = 'submit' value = 'finished'></form><br>";
echo "";
    } else {
    echo "0 results";
}
$conn->close();

 ?>

It always results in
Notice: Undefined index: radio0 in C:\\xampp\\htdocs\\Bootstrap\\radio.php here is an example output Even tho the index radio0 exists in the element of the html.

Answer 1

Let's go through the code little by little

for ($t=0;$t<4;$t++){}

This is an empty for loop. The brackets { and } should include the actions of the loop. Since they're empty, nothing is happening in this loop

$sql = "SELECT * FROM questions LIMIT $t";

You can't use the $t variable here, because it is out of scope. Even if you could, I doubt this is what you really want, since LIMIT merely limits the number of responses you can get.

$result = $conn->query($sql);

You havn't defined a connection object (assuming you've provided all your code).

 $i = 0; echo  " <form action='radio.php' method='post'><table>";

It is really terrible practice to define these things on the same line (although it is possible).

<th>Answers</th>     </tr> <tr>" ;while($row = $result->fetch_assoc()) {

Again, terribly practice - it is very difficult to read.

$ans=array($row['1'],$row['2'],$row['3']);

You should most likely be using integer indexes instead of strings. Furthermore remember that arrays are 0 -indexed.

foreach ($ans as $choice) {echo "<input type='radio' name='radio$i' value = '$choice'>".$choice."<br>";
 } unset($choice);
              echo " </tr>";$i++;}

You havn't defined any $i variable in your loop, so you can't use the $i variable