函数的结果怎么赋值给变量啊

Question

<?php $name = 'stefen'; $tel = '10795856'; $motto = 'If you shed tears when you miss the sun,then you would miss the stars'; function totalLen(...$string){ //=print_r($string); foreach ($string as $content) { echo strlen($content).','; } } $arrNum = totalLen($name,$tel,$motto); //totalLen($name,$tel,$motto)会得到6,8,69，但是貌似不能赋值给$arrNum echo array_sum(array($arrNum)); 我想实现的功能是，无论有多少变量传入函数，都能自动计算出所有字符的长度的和，但是现在没办法把得到的结果赋值给变量，求指教