Question

I have an array of numbers and some numbers are obviously too big or too small relative to them all. I wonder if there is already some kind of function or algorithm that I can use in order to remove these records from array.

Here is an example of array

8
7
21
1330829238608
6
7
188
8
25
92433
19
6

At the moment all I can think about is just check if number is more than 1k or less than 1k and then do not allow it. But still I get problem since 188 does not belong here either.

Is there any good way that I can get majority of close numbers from this array and produce something like

8
7
6
7
8
6

This is what I have so far

<?php

echo '<pre>';
$startArray = Array(8, 7, 21, 1330829238608, 6, 7, 188, 8, 25, 92433, 19, 6);

print_r($startArray);

for ($i = 0; $i < count($startArray); $i++) {
    if ($i != count($startArray) - 1) {
        if ($startArray[$i] - 10 <= $startArray[$i + 1]) {
            echo $startArray[$i] . '<br />';
        }
    }
}

Answer 1

This can be optimized but this is what I figured out, works with diff of 20%, you can change it to whatever % you want, of course.

<?php

$startArray = array(8, 7, 21, 1330829238608, 6, 7, 188, 8, 25, 92433, 19, 6);
$groupArray = array();
$startArrayCount = count($startArray);

for ($i = 0; $i < $startArrayCount; $i++) {
    // 20% of current value
    $valueDiff = ($startArray[$i] / 100) * 20;

    // Get minimal and maximal value
    $maxValue = ($startArray[$i] + $valueDiff);
    $minValue = ($startArray[$i] - $valueDiff);

    // Print it out
//    echo 'Diff: ' . $valueDiff . '<br />';
//    echo 'Max: ' . $maxValue . '<br />';
//    echo 'Min: ' . $minValue . '<br />';

    $groupArray[$i] = array();
    for ($n = 0; $n < $startArrayCount; $n++) {
        if ($startArray[$n] <= $maxValue && $startArray[$n] >= $minValue) {
            // echo 'TRUE: ' . $startArray[$n] . '<br />';
            array_push($groupArray[$i], $startArray[$n]);
        }
    }
    //echo '<hr />';
}

// Getting arrays that have most members in it
$max = count($groupArray[0]);
foreach ($groupArray as $group) {
    if (count($group) > $max) {
        $max = count($group);
    }
}

// Taking all those arrays and combining them in one
$finishArray = array();
foreach ($groupArray as $group) {
    if (count($group) == $max) {
        foreach ($group as $key) {
            array_push($finishArray, $key);
        }
    }
}

// Combining all values
$total = null;
foreach ($finishArray as $num) {
    $total = $total + $num;
}

// Getting average
$average = $total / count($finishArray);

echo $average;