How to make for loop produce five unique values - php

Question

I created this code so that it will give me five value based on probability. Then insert into an array. It works but I want it to give me 5 unique value. If I used array_unique() it will make the output unique so the end result will be 3 or 2 or sometimes 4 value because it removes duplicates. but I want them to be 5 unique values all the time. How can I do This.
This is my code
<?php
$random= [];
function getRandomWeightedElement(array $weightedValues)
{
$array = array();
foreach ($weightedValues as $key => $weight) {
$array = array_merge(array_fill(0, $weight, $key), $array);
}
return $array[array_rand($array)];
}
global $res;
for($i=0; $i<5 ; $i++)
{
$res=getRandomWeightedElement(array('A'=>0.05, 'B'=>0.05,'C'=>0.10,'D'=>5,'E'=>5,'F'=>5,'G'=>5,'H'=>13,'I'=>16,'J'=>16,'K'=>16.8,'L'=>18));
global $stopAt;
if ($res=='A') {
$stopAt = 20;
} else if ($res=='B') {
$stopAt = 50;
} else if ($res=='C') {
$stopAt = 70;
} else if ($res=='D') {
$stopAt = 100;
} else if ($res=='E') {
$stopAt = 135;
} else if ($res=='F') {
$stopAt = 165;
continue;
} else if ($res=='G') {
$stopAt = 190;
} else if ($res=='H') {
$stopAt = 230;
} else if ($res=='I') {
$stopAt = 265;
} else if ($res=='J') {
$stopAt = 292;
} else if ($res=='K') {
$stopAt = 320;
} else if ($res=='L') {
$stopAt = 350;
} else{
echo "error";
}
$random[]= $stopAt;
}
print_r(array_unique($random));
?>

Answer 1

You will have to check if the value already exists in the result array, you can use in_array() for that. But that means you have to keep looping until you have 5 unique results which means changing the loop.
$random= [];
function getRandomWeightedElement(array $weightedValues)
{
$array = array();
foreach ($weightedValues as $key => $weight) {
$array = array_merge(array_fill(0, $weight, $key), $array);
}
return $array[array_rand($array)];
}
//for($i=0; $i<5 ; $i++) {
$params = array('A'=>0.05, 'B'=>0.05,'C'=>0.10,'D'=>5,
'E'=>5,'F'=>5,'G'=>5,'H'=>13,'I'=>16,
'J'=>16,'K'=>16.8,'L'=>18);
$notGot5 = true;
while ( $notGot5 ) {
$res=getRandomWeightedElement($params);
if ($res=='A') {
$stopAt = 20;
} else if ($res=='B') {
$stopAt = 50;
} else if ($res=='C') {
$stopAt = 70;
} else if ($res=='D') {
$stopAt = 100;
} else if ($res=='E') {
$stopAt = 135;
} else if ($res=='F') {
$stopAt = 165;
continue;
} else if ($res=='G') {
$stopAt = 190;
} else if ($res=='H') {
$stopAt = 230;
} else if ($res=='I') {
$stopAt = 265;
} else if ($res=='J') {
$stopAt = 292;
} else if ($res=='K') {
$stopAt = 320;
} else if ($res=='L') {
$stopAt = 350;
} else{
echo "error";
}
if ( in_array($stopAt, $random) ) {
// keep looking
continue;
} else {
$random[]= $stopAt;
}
// loop terminates when we have 5 in the array
$notGot5 = count($randon) != 5;
}
print_r($random);

Answer 2

Instead of doing several if statements to choose random values, you can choose the values directly from the array itself.
The below code should give you what you want:
$valuesToChooseFrom = [
'A' => 0.1,
'B' => 0.3,
'C' => 3.1,
'D' => 20,
'E' => 10,
'F' => 4,
'G' => 222
];
$result = [];
for ($i = 0; $i < 5; $i++) {
$key = array_rand($valuesToChooseFrom);
$result[$key] = $valuesToChooseFrom[$key];
unset($valuesToChooseFrom[$key]);
}
print_r($result);
And gives:
Array
(
[F] => 4
[G] => 222
[D] => 20
[B] => 0.3
[E] => 10
)
It works by selecting a random element from the valuesToChooseFrom array, using the array_rand() function. The array_rand function selects a random element from the array you pass it, and returns that element (the key in this case, since we are working with a 2 dimensional array). You then add an item to the result array, with the key being the key returned from the array_rand call, and the value being the value in the valuesToChooseFrom array, using the key to index the valuesToChooseFrom array.
To prevent PHP from choosing the same value more than once, you have to remove the value valuesToChooseFrom array. This is what the unset($valuesToChooseFrom[$key]); line does.
array_rand() also accepts a second argument, which is the number of random elements to select from the array. If you pass in 5 as the second argument, it will choose 5 random elements from the array. And since they all appear to be unique (I could be mistaken), a better way would be to do array_random($valuesToChooseFrom, 5) to select 5 random values from the array.
But since that method only returns the keys, you will need to do a foreach loop to loop over the returned array, and then use each key to grab the value from the valuesToChooseFrom array.