Generate random float numbers in range PHP

问题:

I have a code that initializes a dice object by the following code:

public function initializeDiceSides($totalSides, $fair, $maxProbability = 100) {
   $maxTemp = $maxProbability;
   $sides = array();

   for ($side = 0; $side < $totalSides; $side++) {
     //if we want fair dice just generate same probabilities for each side
     if ($fair === true) {
       $probability = number_format($maxProbability/$totalSides, 5);
     } else {
       //set probability to random number between 1 and half of $maxTemp
       $probability = number_format(mt_rand(1, $maxTemp/2), 5);

       //subtract probability of current side from maxtemp
       $maxTemp= $maxTemp- $probability;

       $sides[$side] = $probability;
     }
   }

   echo $total . '<br />';
   print_r($sides);
}

above code prints:

89
Array ( [0] => 48.00000 [1] => 13.00000 [2] => 14.00000 
        [3] => 9.00000 [4] => 2.00000 [5] => 2.00000 )

I want to be able to generate float numbers instead of integers, I want to have something like

Array ( [0] => 48.051212 [1] => 13.661212 [2] => 14.00031 
        [3] => 9.156212 [4] => 2.061512 [5] => 2.00000 )

回答1:

A simple approach would be to use lcg_value and multiply with the range and add the min value

function random_float ($min,$max) {
    return ($min + lcg_value()*(abs($max - $min)));
}

回答2:

I'd just generate random numbers from 0 to 999999 and then divide them by 100000

回答3:

You could multiply the variables that you feed into mt_random by a factor of, say, 100000, and then divide the output by the same factor to get a float value.

回答4:

function random_float($min = 0, $max = 1, $includeMax = false) {
    return $min + \mt_rand(0, (\mt_getrandmax() - ($includeMax ? 0 : 1))) / \mt_getrandmax() * ($max - $min);
}

回答5:

Make sure the value of $maxProbability and $totalSides are floats.
If they are integers, the result will be typed as an integer.