How to count how many duplicates an array has in Php - php

Question

I'm new to Php and today I came across the rand()-function. I'd like to fill an array with numbers created with this function and then count the number of its duplicates. I already tried it a first time, but somehow I seem to be on the woodway.
<?php
$numbers = array();
for ($i=0; $i < 100; $i++) {
$numbers[$i] = rand(0, 100);
}
//$numbers = array(12,12,12,12);
echo "random numbers generated.<br>";
$arrLength = count($numbers);
$arrWithDoubles = array();
for ($i=0; $i < $arrLength; $i++) {
//echo "start looping for i: ".$i."! numbers['i'] has the content".$numbers[$i].".<br>";
for ($x=$i; $x < $arrLength; $x++) {
//echo "looped for x: ".$x."! numbers['x'] has the content".$numbers[$x].".<br>";
if($numbers[$i] == $numbers[$x]) {
if($i != $x) {
//echo "pushed to 'arrWithDoubles'.<br>";
array_push($arrWithDoubles, $numbers[$x]);
}
}
}
}
echo "numbers of doubles: ".count($arrWithDoubles)."<br>";
echo "list of numbers which were double:<br>";
for ($i=0; $i < count($arrWithDoubles); $i++) {
echo $arrWithDoubles[$i];
echo "<br>";
}
?>

Answer 1

The array_unique() function removes duplicates from an array, then just add a bit of math.
<?php
$numberOfDuplicates = count($orginalArray) - (count($orginalArray) - count(array_unique($originalArray)));
?>

Answer 2

$origin = array(2,4,5,4,6,2);
$count_origin = count($origin);
$unique = array_unique($origin);
$count_unique = count($unique);
$duplicates = $count_origin - $count_unique;
echo $duplicates;

Answer 3

$count = array();
foreach ($srcRandom as $sr) {
if (!array_key_exists ($sr, $count) ) {
$count[$sr] = 1;
continue;
}
$count[$sr]++;
}
var_dump ($count);

Answer 4

Thanks for all your input. With that I came to the following solution which fits my demand the best:
<?php
function countValueInArray($value, $array) {
$count = 0;
for ($i=0; $i < count($array); $i++) {
if($value == $array[$i]) {
$count++;
}
}
return $count;
}
$numbers = array();
for ($i=0; $i < 100; $i++) {
$numbers[$i] = rand(0, 100);
}
$duplicates = array();
for ($x=0; $x < count($numbers); $x++) {
$number = countValueInArray($numbers[$x], $numbers);
if ($number > 1) {
array_push($duplicates, $numbers[$x]);
}
}
$duplicatesList = array_values(array_unique($duplicates));
echo "number of duplicates: ".count($duplicatesList);
echo "<br>these are: <br>";
print_r($duplicatesList);
?>
Thanks a lot for your help!