array_map和闭包操作php数组总结

<?php
$a = [];
$b = ["Horse","Dog","Cat"];

array_map(function ($value) use (&$a){

	if($value==="Dog"){$a[] = $value;}},

$b);
print_r($a);

$a1 = ["Horse","Dog","Cat"];
$a2 = ["Cow","Dog","Rat"];
$a3 = [];
array_map(function ($v1,$v2) use (&$a3) {
   
  if($v1==$v2){

    //unset($v1);
    $a3[] = $v1;
     //var_dump($v1);
  }
},$a1,$a2);

var_dump($a3);

array_walk($a = ["a"=>"red","b"=>"green","c"=>"blue"], function ($value,$key){

    echo $key.'------'.$value;
});

 $a2 = ["Cow","Dog","Rat","Dog","Pig"];
 $arr = [];

 $new_arr = array_map(function ($item) use (&$arr) {

 	  if(!in_array($item,$arr)){

 	  	  $arr[] = $item;
 	  	  return $item;
 	  }

 	  return false;

 },$a2);

var_dump( $new_arr);