[Solved] get extremes from list of numbers [closed]

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Mine’s similar to jprofitt’s

but I divided them into peaks and valleys, so I can do some more stuff with it.

I think his loop is much more cleaner than mine is, but I just wanted to test it out for myself.
Don’t judge meeeeee

This script just plots the points out and selects the peaks and valleys and give them green and red respectively. See it as a visual aid. 😛

graph

<?php

$plot = array(10,9,8,8,9,7,6,5,4,6,7,8,11,10,12,14,16,20,30,29,28,29,27,25,20,18,15,10,8,5,4,1);

$res = local_extremes($plot);

function local_extremes(array $array){
    $peaks = array();
    $valleys = array();

    $peak_keys = array();
    $valley_keys = array();

    for($i = 0; $i < count($array); $i++){
        $more_than_last = $array[$i] > $array[$i-1];
        $more_than_next = $array[$i] > $array[$i+1];

        $next_is_equal = $array[$i] == $array[$i+1];

        if($next_is_equal) continue;

        if($i == 0){
            if($more_than_next){
                $peaks[] = $array[$i];
                $peak_keys[] = $i;
            }else{
                $valleys[] = $array[$i];
                $valley_keys[] = $i;
            }
        }elseif($i == (count($array)-1)){
            if($more_than_last){
                $peaks[] = $array[$i];
                $peak_keys[] = $i;
            }else{
                $valleys[] = $array[$i];
                $valley_keys[] = $i;
            }
        }else{
            if($more_than_last && $more_than_next){
                $peaks[] = $array[$i];
                $peak_keys[] = $i;
            }elseif(!$more_than_last && !$more_than_next){
                $valleys[] = $array[$i];
                $valley_keys[] = $i;
            }
        }
    }

    return array("peaks" => $peaks, "valleys" => $valleys, "peak_keys" => $peak_keys, "valley_keys" => $valley_keys);
}
?>

<style type="text/css">
    .container{
        position: absolute;
    }

    .point{
        position: absolute;
        width: 4px;
        height: 4px;
        background: black;
    }

    .extreme{
        position: absolute;
        top: 5px;
    }

    .extr_low{
        background: red;
    }

    .extr_high{
        background: green;
    }
</style>

<?php

//Plot
echo "<div class="container">";
foreach($plot as $key => $point){
    $left = ($key*10);
    $top = 400 - ($point*10);

    if(in_array($key, $res['peak_keys']) || in_array($key, $res['valley_keys'])){
        $extreme = "<div class="extreme">$point</div>";
    }else{
        $extreme = "";
    }

    if(in_array($key, $res['peak_keys'])){
        $xc = "extr_high";
    }elseif(in_array($key, $res['valley_keys'])){
        $xc = "extr_low";
    }else{
        $xc = "";
    }

    echo "<div class="point $xc" style="left: ".$left."px; top: ".$top."px;">$extreme</div>";
}
echo "</div>";

?>

<table>
    <tr>
        <th>&nbsp;</th>
        <th>Valley</th>
        <th>Peak</th>
    </tr>
    <tr>
        <th>Lowest</th>

        <td><?php echo min($res['valleys']); ?></td>
        <td><?php echo min($res['peaks']); ?></td>
    </tr>
    <tr>
        <th>Highest</th>
        <td><?php echo max($res['valleys']); ?></td>
        <td><?php echo max($res['peaks']); ?></td>
    </tr>
</table>

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solved get extremes from list of numbers [closed]