Functions about random numbers - php

Question

How can I create functions that answer to:
How many different numbers were generated during simulation?
% Of appearance of the numbers from 0 to 50 ?
What is the number that appeared several times during the simulation?
function randomDigits($numDigits) {
$arrayRange = 1000;
if ($numDigits <= 0) {
return '';
} else{
for($i=0; $i<$arrayRange; $i++){
echo mt_rand(0, 50) ." ";
}
}
}
$maxq = 100;
for ($i = 1; $i <= $maxq; $i++) {
echo $i . "<br>\n";
randomDigits($i) . "<br>\n----<br>\n";
}

Answer 1

If you store all the generated numbers into an array, you could use array_count_values()
This will count the occurrences of multiple key values in your array (e.g. if there are 12 occurrences of the number 7) and return the result in an array. This will only work for strings and integer values.
<?php
$array = ['a', 'a', 'a', 'a', 'b', 'b', 'c'];
print_r(array_count_values($array));
?>
Results from the above:
Array(
[a] => 4
[b] => 2
[c] => 1
)
From there, you should be able to easily do all the methods and outputs that you wish.
Here is the basic integration with your existing code...
<?php
$maxq = 100;
$returned_array = [];
for ($i = 1; $i <= $maxq; $i++) {
$returned_array = randomDigits($i); // return the generated array
// merge 'add' the two arrays, like saying i = i +2 or
// merged_array = merged_array + array
array_merge($returned_array, $returned_array);
// here you now have one array of 1000 random values
// print_r($returned_array);
// lets do some math
print_r(array_count_values($returned_array));
// this will show how many values were duplicates...
// e.g
// Array (
// [43] => 25 the number 43 was generated 25 times
// [25] => 22 the number 25 was generated 22 times
// [1] => 28 ect...
// you can loop through this array here and see which value was generated several times,
// format the results nicely, and do all sorts of maths on it as you wish
}
function randomDigits($numDigits) {
$arrayRange = 1000;
$generated_array = []; // here is an actual array that will store the generated numbers
if ($numDigits <= 0) {
return null;
} else {
for($i = 0; $i < $arrayRange; $i++) {
$random = mt_rand(0, 50);
array_push($generated_array, $random); // add the random value to the array
}
// here you have your array of generated numbers
return $generated_array;
}
}
?>

Answer 2

Example here - http://codepad.org/9Dv1CwR7
Sequence generation contains random integers for given length
function generate_array($count, $min, $max) {
$arr = array();
for ($i=0; $i<$count; $i++) {
$arr[$i] = rand($min, $max);
}
return $arr;
}
Calculating percentage of given interval (with a helper function):
function cnt($element, $arr){
$cnt = array_count_values($arr);
return $cnt[$element];
}
function percentages($min, $max, $arr) {
$total = sizeof($arr);
$occurences = 0;
while ($min < $max) {
if (!array_key_exists($min, $arr)) {
continue;
} else {
$occurences = $occurences + cnt($min, $arr);
}
$min++;
}
return $occurences/$total;
}

Answer 3

Add all simulated values to an array, and use array_count_values to get all unique values.
function randomDigits($numDigits) {
$arrayRange = 1000;
if ($numDigits <= 0) {
return '';
} else{
$arr=array();
for($i=0; $i<$arrayRange; $i++){
$val=mt_rand(0, 50);
$arr[]=$val;
echo $val ." ";
}
echo "\n";
$arr=array_count_values($arr);
echo "Total Unique numbers:".count($arr);
}
}
$maxq = 100;
for ($i = 1; $i <= $maxq; $i++) {
randomDigits($i) . "<br>\n----<br>\n";
}