Generate Numbers from array except for the ones from another array

[President Obama]

$bl = array(); 
$link1 = array_rand($cds); 
$link2 = array_rand($cds); 
$link3 = array_rand($cds); 
$link4 = array_rand($cds); 
$A = 0;
while (!in_array($link1, $bl)){
$link1 = array_rand($cds);
$bl[$A] = $link1;
$A++;
}
while (!in_array($link2, $bl)){
$link2 = array_rand($cds);
$bl[$A] = $link2;
$A++;
}
while (!in_array($link3, $bl)){
$link3 = array_rand($cds);
$bl[$A] = $link3;
$A++;
}
while (!in_array($link4, $cds)){
$link4 = array_rand($cds);
$bl[$A] = $link4;
$A++;
}
echo $link1;
echo $link2;
echo $link3;
echo $link4;

 

Pretty much I'm trying to generate 4 number's between the min and max of an array but I don't want any duplicates. So it checks if the number exists in a bl array if it does it generates another number, well thats the theory. Doesn't work like that though.

[PaulRyan]

Something like this should do.

 

<?PHP

  $cds    = array('0','1','4','6','12','14','17','20');
  $result = array();

  $numberCount = 4;
  $thisCount   = 0;

  while($thisCount<$numberCount) {
    $thisNumber = array_rand($cds);
    if(!in_array($thisNumber, $result)) {
      $result[$thisCount] = $thisNumber; $thisCount++;
    }
  }

  print_r($result);
?>

 

Try the code and tell me how it goes

 

Regards, PaulRyan.

 

[President Obama]

Thanks so much that worked perfectly.

[Psycho]

Instead of building an inefficient while() loop, just use the function that PHP already provides! array_rand() takes a second, optional parameter for the number of random values to get.

$links = array_rand($cds, 4);

 

$links will then old the random keys that you can use to reference the values of the links

[Psycho]

Two more efficient methods of getting the four values would be as follows:

 

$links = array_intersect_key($cds, array_fill_keys(array_rand($cds, 4), 0));

 

OR

 

$links = $cds;
shuffle($links);
$links = array_slice($links, 0, 4);