php random number within range - no repeat

Question

Haven't been able to find what I'm looking for so far, so I'm asking for help.

I have a div with a class that needs to end in a number between 1 and 8, and I need it to be a random number, without repeating...

<div class="parallax parallax_<?php echo $random_number ?>"></div>

I figured this should be pretty simple, but I'm having trouble.

Currently, I have:

<div class="parallax parallax_<?php echo rand(1, 8); ?>"></div>

which works, but produces duplicates.

EDIT

So after testing, I realized I am running into a problem. I am using this within a wordpress template. I am querying a set of 6 posts, and for each set of posts, I am including the above parallax div. So, I get a random, none repeating number for each query, but each query resets the numbers - giving me duplicates... Here is my entire code.

<?php
  $args = array(
    'post_type'        => 'post',
    'orderby'          => 'menu_order',
    'posts_per_page'   => -1,
    'order'            => 'ASC'
  );
  $posts = get_posts( $args );
?>

<?php foreach (array_chunk($posts, 6, true) as $posts) :  ?>
  <div class="parallax parallax_<?php echo rand(1, 8); ?>"></div>
  <div class="posts_container">  
    <?php foreach( $posts as $post ) : setup_postdata($post); ?>

      <div class="post">
        <div class="post__thumbnail"><a href="<?php the_permalink();?>"><?php the_post_thumbnail(); ?></a></div>
        <div class="post__title"><?php the_title(); ?></div>
      </div>

    <?php endforeach; ?> 
  </div>
<?php endforeach; ?>

random number, without repeating is not strictly a randon number — RiggsFolly
– RiggsFolly, Commented Oct 5, 2016 at 13:08
Possible duplicate of Generating random numbers without repeats — Thamaraiselvam
– Thamaraiselvam, Commented Oct 5, 2016 at 13:21
I think that EDIT is a big enough change to the question to warant you asking it as a new question — RiggsFolly
– RiggsFolly, Commented Oct 5, 2016 at 13:48

Praveen Kumar Purushothaman · Accepted Answer · 2016-10-05 13:07:53Z

5

I would do a range and shuffle:

$myRange = range(1, 8);
shuffle($myRange);
return $myRange[0];

answered Oct 5, 2016 at 13:07

Praveen Kumar Purushothaman

167k27 gold badges215 silver badges261 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

syck Over a year ago

Would be better to make the array static and pop one value off of it at a time. But using shuffle() is elegant and terse.

Praveen Kumar Purushothaman Over a year ago

@RiggsFolly Didn't expect this from you. Just loop $myRange, which is what I intended.

RiggsFolly Over a year ago

I did say that I may have misunderstood how to run in 8 times correctly

RiggsFolly Over a year ago

@PraveenKumar Google translate does not make that good a job of it I am afraid, but I did guess Tamil

Praveen Kumar Purushothaman Over a year ago

@RiggsFolly Google Translate is still a baby in terms of South Indian languages.

|

Andrej Buday · Accepted Answer · 2016-10-05 13:34:26Z

4

This code prevent duplicate and fits to any other test case scenario. Shuffling is not necessary, random element is based on array_rand() function.

To pick repetitively new random key it is necessary to use code in the loop.

// Array declaration
$a=array(1,2,3,4,5,6,7,8);

// Loop
$randomKey=array_rand($a);
unset($a[$randomKey]);

// Test
echo $randomKey."<br>";
var_dump($a);

First it is defined an array of numbers which are desired. Than random key from array is picked. It is also unset from array so it will be not used again.

For repeating action $randomKey and unset() should be in loop. Echo and var_dump() function is only for testing purpose. Array size can decrease unsetting already used key or stay same length leaving unset() function from the loop.

edited Oct 5, 2016 at 13:34

answered Oct 5, 2016 at 13:16

Andrej Buday

6297 silver badges14 bronze badges

2 Comments

RiggsFolly Over a year ago

This looks good but should echo $a[$randomKey]; and move the unset to after you echo the number!!!!!

Andrej Buday Over a year ago

Order doesn't matter. You can do as you please, test part is only for informative purpose.

Thamaraiselvam · Accepted Answer · 2016-10-05 13:23:16Z

0

I think this could help you. shuffle() here

<?php
$numbers = range(1, 8);
shuffle($numbers);
foreach ($numbers as $number) {
    echo "$number ";
}

edited Oct 5, 2016 at 13:23

answered Oct 5, 2016 at 13:13

Thamaraiselvam

7,1128 gold badges51 silver badges73 bronze badges

Comments

Ionut Necula · Accepted Answer · 2016-10-05 13:42:14Z

0

You can use uniqid() function along with md5 to strengthen the results:

 md5(uniqid(rand(1, 8), true));

Or use shuffle.

$numbers = range(1, 8);
shuffle($numbers);

foreach ($numbers as $number) {
    echo "$number ";
}

edited Oct 5, 2016 at 13:42

answered Oct 5, 2016 at 13:07

Ionut Necula

11.6k4 gold badges49 silver badges72 bronze badges

3 Comments

syck Over a year ago

Does not prevent duplicates.

syck Over a year ago

And uniqid() and md5() do not make the result more random.

Ionut Necula Over a year ago

Maybe, but it's a start. Also in the loop he can add a counter to the end of each number to make it even more unique. Please do post a better answer. I dare you.

Collectives™ on Stack Overflow

php random number within range - no repeat

4 Answers 4

11 Comments

2 Comments

Comments

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

11 Comments

2 Comments

Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related