CODEWITHSUNDEEP
phparraysrandom
Bang Roy Han
Bang Roy Han

Reputation: 97

How to retrieve random elements from php array excluding specific elements

Please I need some help. I have the array given below and I want to return random elements from it.

$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$rand = rand(0,count($data)-1);
echo $data[$rand];

The code above works as expected. However, I wan't to be able to exclude specific elements from the returned list as given below:

$exclude = "Mouse";
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$rand = rand(0,count($data)-1);
echo $data[$rand];

The expected result is that the element specified in $exclude "Mouse" in this case will not be returned as one of the random elements.

Maybe the mouse element will first be removed from the array as seen below then a random element will be returned:

$data = array('Computer', 'Laptop', 'Keyboard');

Upvotes: 2

Views: 1949

Answers (5)

Domain
Domain

Reputation: 11808

You can prepare a new array and store the strings without excluded string as: 

$exclude = "Mouse";
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$exclude_arr=array();

foreach ($data as $single)
{
 if($single !== $exclude)
     $exclude_arr[]=$single;
}
//Here you have the array exclude_arr without the exclude string
$rand = rand(0,count($exclude_arr)-1);
echo $exclude_arr[$rand];

execute rand() function as usual and echo it

Upvotes: 0

AndreyS Scherbakov
AndreyS Scherbakov

Reputation: 2788

I think you are right and the best solution for such scales is array filtering. Say,

$exclude = "Mouse";

function noexc($var) {
    global $exclude;
    return ($exclude != $var);
}

$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$fdata = array_filter($data, "noexc");
$rand = rand(0,count($fdata)-1);
echo $fdata[$rand];

Upvotes: 0

Sougata Bose
Sougata Bose

Reputation: 31749

A recursive function may help - 

function select_rand($exclude, $array) {
   $rand = rand(0,count($array)-1);
   if($array[$rand] == $exclude) {
       select_rand($exclude, $array);
   }
   else
   {
       echo $array[$rand] ;
   }
}

$exclude = "Mouse";
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
select_rand($exclude, $data);

Or 

$exclude = "Mouse";
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$temp = array_diff($data, array($exclude));
echo $temp[rand(0, sizeOf($temp))];

Upvotes: 0

Rene Korss
Rene Korss

Reputation: 5484

You could use array_diff to remove values in $exclude from $data.

$exclude = array('Mouse');
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$excluded_data = array_values(array_diff($data, $exclude));
$rand = rand(0,count($excluded_data)-1);
echo $excluded_data[$rand];

This code removes Mouse from $data and then gets random value from new array. Array for random data will be like you described:

$data = array('Computer', 'Laptop', 'Keyboard');

Upvotes: 3

ManiMuthuPandi
ManiMuthuPandi

Reputation: 1604

Try this

$exclude = "Mouse";
$data = array('Computer', 'Laptop', 'Mouse', 'Keyboard');
$dummy_data=$data ;
$key=(array_keys($dummy_data,$exclude));
$key=$key[0];
unset($dummy_data[$key]);
$rand = rand(0,count($dummy_data)-1);
//print_r($dummy_data);
if(isset($dummy_data[$rand]))
echo $dummy_data[$rand];
else
echo"Record Missing";

Upvotes: -1

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