php数组中某些值的总和[关闭]

I have this array`

<?php
$arr = [['name'=>'john','age'=>20,'sex'=>'m'],
        ['name'=>'maria','age'=>12,'sex'=>'f'],
        ['name'=>'nick','age'=>25,'sex'=>'m'],
        ['name'=>'jo','age'=>31,'sex'=>'f'],];
foreach ($arr as $persoana) {
  foreach ($persoana as $id=>$value) {
    if ($id == 'age') {
        $sumvarsta = $sumvarsta + $value;
        $n++;
    }
  }
}`?>

i need total average age (total average age seems to be working ok) , average age for women and average age for men. How to calculate ?

thx.

<?php
$arr = [['name'=>'john','age'=>20,'sex'=>'m'],
        ['name'=>'maria','age'=>12,'sex'=>'f'],
        ['name'=>'nick','age'=>25,'sex'=>'m'],
        ['name'=>'jo','age'=>31,'sex'=>'f'],];

$womansum = 0;
$womancount = 0;
$mansum = 0;
$mancount = 0;

foreach ($arr as $persoana) {

  if ($persoana['sex'] == 'm')
  {
    $mansum += $persoana['age'];
    $mancount++;
  } else {
    $womansum += $persoana['age'];
    $womancount++;
  }

}

$manAverage = $mansum / $mancount;

$womanAverage = $womansum / $womancount;

$totalAverage = ($mansum + $womansum) / ($mancount + $womancount);


?>