What is the quickest way to randomize a data set? - php

Question

For a multiple choice quiz application i would like to show the dummy answers with the correct answer. But with the correct answer being in a different position at each different question.
This is what i've tried but it doesn't seem to be working:
if ($question->type == 1)
{
echo "<div id='dummy_answers'>";
//Show Dummy
echo '<h3>Dummy Answers</h3>';
//Get Dummy Answers
$query = $this->test_model->getDummyAnswers($question->id);
$dummy_num = 1;
foreach ($query->result() as $row)
{
$rand_number = rand(1, 3);
if ($dummy_num == $rand_number)
{
$dummy_num = $rand_number + 2;
echo '<h4>Answer '.$dummy_num.'</h4>';
echo '<p>';
echo $row->option;
echo '</p>';
//Now echo the real answer
echo '<h4>Answer '.$rand_number.'</h4>';
echo '<p>';
echo $row->option;
echo '</p>'; //Get id's for each.echo $row->id;
}
else
{
echo '<h4>Answer '.$dummy_num.'</h4>';
echo '<p>';
echo $row->option;
echo '</p>';
$dummy_num++;
}
}
echo '</div>';
echo ' <hr/>';
}
?>

Answer 1

You should use shuffle function.
In your case it will be:
if ($question->type == 1)
{
echo "<div id='dummy_answers'>";
//Show Dummy
echo '<h3>Dummy Answers</h3>';
//Get Dummy Answers
$query = $this->test_model->getDummyAnswers($question->id);
$answers=$query->result();
shuffle($answers);
foreach ($answers as $nr=>$row)
{
echo '<h4>Answer '.($nr+1).'</h4>';
echo '<p>';
echo $row->option;
echo '</p>';
}
echo '</div>';
echo ' <hr/>';
}
?>

Answer 2

Put the answers in an array the use shuffle
$random_array = shuffle($answers);

Answer 3

All you need to do is put the keys for your answers in an array and call shuffle(). Something like this:
$keys = array_keys($answers);
shuffle($keys);
for ($key in $keys) {
echo $answers[$key];
}

Answer 4

I would suggest putting all the answers into an array and using the shuffle() function to randomize them. Once they're shuffled, just iterate the array with a loop and build the markup.

Answer 5

You could put the results into an array (1 correct and 3 incorrect), then shuffle, then output them?
$answers = array();
array_push($answers, "answer1");
array_push($answers, "answer2");
array_push($answers, "answer3");
array_push($answers, "answer4");
shuffle($answers);
foreach ($answers as $answer) {
echo $answer;
}