PHP计算显示平均温度、五个最低及最高温度

<?php
$month_temp = "78, 60, 62, 68, 71, 68, 73, 85, 66, 64, 76, 63, 81, 76, 73,
68, 72, 73, 75, 65, 74, 63, 67, 65, 64, 68, 73, 75, 79, 73";
$temp_array = explode(&#39;,&#39;, $month_temp);
$tot_temp = 0;
$temp_array_length = count($temp_array);
foreach($temp_array as $temp)
{
    $tot_temp += $temp;
}
$avg_high_temp = $tot_temp/$temp_array_length;
echo "平均温度为: ".$avg_high_temp."
";
sort($temp_array);
echo " 五个最低温度：";
for ($i=0; $i< 5; $i++)
{
    echo $temp_array[$i].", ";
}
echo "五个最高温度：";
for ($i=($temp_array_length-5); $i< ($temp_array_length); $i++)
{
    echo $temp_array[$i].", ";
}

平均温度为：70.6                               
五个最低温度：60,62,63,63,64，
五个最高温度：76,78,79,81,85，