for循环 求数组平均数和总数

<?php

$arr = [\'a\'=>18,20,\'cc\'=>10,2=>11];
$arrLen = count($arr);
$count = $sum= 0;
for($i=0;$i<$arrLen;$i++)
{
  $key = key($arr);
  $current = current($arr);
  $count++;
  next($arr);//下一个
  
  $sum +=$current;
}
echo \'总数:\'.$sum.\'平均数是\'.$sum/$count;