How to use PHP Arrays to receive random numbers with no duplicating

Question

I can't provide the HTML due to my site not being live. Though I know from theory coding a professional will hopefully be able to follow my logic.

• Please point out with my code how I can get this working, as I see the following link is similar but not exactly the same scenario. I'm confused how to apply it to my following code:

Generating random numbers without repeats

My Goal I want to use PHP to create the following:

1. Place 00 to 99 into an array.
2. Retrieve a random number from the array.
3. Store/Use the retrieved random from the array to place in a mysql_query as seen with number = $question Note here (Do I really require ORDER BY RAND() here?)
4. Remove the selected random number from the array list of numbers
5. Fetch and display the random number
6. Once all numbers have been used then an error displays saying, refresh page to reset numbers.

The next time I want another random number it cannot duplicate the same random number it selected from the array before. So if I used the code above say 109 times then only 1 number is left in the array.

Code (Edited):

   <?php

  //--------------------------------------------------------------------------
  // Example php script for fetching data from mysql database
  //--------------------------------------------------------------------------
  $host = "localhost";
  $user = "root";
  $pass = "";

  $databaseName = "monkeyscanfly";
  $tableName = "num_image";

  //--------------------------------------------------------------------------
  // 1) Connect to mysql database
  //--------------------------------------------------------------------------
  include 'DB.php';
  $con = mysql_connect($host,$user,$pass);
  $dbs = mysql_select_db($databaseName, $con);

    if(!isset($_SESSION)) {
        session_start();

        $_SESSSION['used'] = [];
    }

    $array = [0,1,2,3,4,5,6,7,8,9,"00","01","02","03","04","05","06","07","08","09",10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99]; 

    while(!empty($array)) {
        $array = array_diff($array, $_SESSSION['used']);

        //pick a random point from the array
        $random = array_rand($array);

        // Save the used element in session
        $_SESSION['used'][] = $array;


        //store the random question number
        $question = $array[$random];

        // Select information from database and use array to assign to the selected row.

        $query = mysql_query("SELECT number, association, image_file, skeleton, sound, colour, comments FROM num_image WHERE number = $question ORDER BY RAND() LIMIT 1");

        // Remove random number that was chosen from the array, so the next time the random number is ran, it won't be found in the array.

        unset($array[$random]);

        //fetch result to print on page

        $arrayss = mysql_fetch_row($query);

        //Echo result as json
        echo json_encode($arrayss);
    }

    if(count($array) == count($_SESSION['used'])) {
        $_SESSION['used'] = [];
    }
?>

I hope this makes sense, I'm having a difficult time find out how to do it, I have searched for hours and can't get my head around it. :)

I forgot to mention that this PHP script will be reloaded by ajax code every time I need a new random number. So it has to store/remember the number with that in mind. If that makes sense?

Answer 1

if I understood your correctly I think this code is what you're looking for. In this case since you're using AJAX we'll be saving used questions like array in session.

<?php
    if(!isset($_SESSION)) {
        session_start();

        $_SESSION['used'] = ((!isset($_SESSION['used'])) ? ([]) : ($_SESSION['used']));
    }

    //--------------------------------------------------------------------------
    // 1) Connect to mysql database
    //--------------------------------------------------------------------------
    include 'DB.php';

    $con = mysql_connect($host, $user, $pass);
    $dbs = mysql_select_db($databaseName, $con);

    $array = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99];
    $array_unique = [];

    while(!empty($array_unique = array_diff($array, $_SESSION['used']))) {
        //pick a random point from the array
        $random = array_rand($array_unique, 1);

        // Save the used element in session
        $_SESSION['used'][] = $array_unique[$random];

        //store the random question number
        $question = $array_unique[$random];

        // Select information from database and use array to assign to the selected row.
        $query = mysql_query("SELECT `number`,`association`,`image_file`,`skeleton`,`sound`,`colour`,`comments` FROM ".$tableName." WHERE `number` = ".$question." LIMIT 0,1");

        //fetch result to print on page

        $row = mysql_fetch_row($query);

        //Echo result as json
        echo json_encode($row);
    }
    if(count($array_unique) == 0) {
        $_SESSION['used'] = [];
    }
?>

Just use while and array_rand