[TOC] # 问题描述 ~~~ $lastYear=[ $lastYear=[ 6345.75, 5454.54, 5235.14, 7313.45, 25353.47, 5235.86 ]; $thisYear=[ 4345.75, 1325.75, 1325.75, 2367.77, 3432.76, 4646.86 ]; ~~~ 这是去年上半年的盈利和今年上半年的盈利,我们要对比这个 # 常规写法 ``` $profit=[]; foreach ($thisYear as $key=>$monthly){ $profit[]=$monthly-$lastYear[$key]; } dd($profit); ``` # collection 我们要处理2个数组,用到zip ~~~ $profit=collect($thisYear)->zip($lastYear); ~~~ 把2个数组压成一个 ~~~ $profit=collect($thisYear)->zip($lastYear)->map(function($value){ //用第一个元素减去最后一个元素 return $value->first()-$value->last(); }); dump($profit); ~~~