Question

How to generate N unique random numbers between min and max in PHP

Answer 1

function generateUniqueRandomNumbers($N, $min, $max) {
    $uniqueNumbers = [];

    if ($N > ($max - $min + 1)) {
        echo "Not enough unique numbers in the given range.";
        return;
    }

    while (count($uniqueNumbers) < $N) {
        $randomNumber = rand($min, $max);
        if (!in_array($randomNumber, $uniqueNumbers)) {
            $uniqueNumbers[] = $randomNumber;
        }
    }

    return $uniqueNumbers;
}

$N = 8;
$uniqueRandomNumbers = generateUniqueRandomNumbers($N, 1, 20);

print_r($uniqueRandomNumbers);


/*
run:

Array
(
    [0] => 16
    [1] => 14
    [2] => 17
    [3] => 3
    [4] => 20
    [5] => 5
    [6] => 4
    [7] => 1
)

*/

 

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Answer 2

function generateUniqueRandomNumbers($N, $min, $max) {
    $uniqueNumbers = [];

    while (count($uniqueNumbers) < $N) {
        $num = rand($min, $max);
        $uniqueNumbers[$num] = true; // Use the number as a key to ensure uniqueness
    }

    return array_keys($uniqueNumbers);
}

$N = 8; // Number of unique random numbers

$randomNumbers = generateUniqueRandomNumbers($N, 1, 20);

foreach ($randomNumbers as $num) {
    echo $num . " ";
}



/*
run:
 
9 7 4 3 15 16 20 17 
 
*/

 

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