PHP recursive function Introduction to Array related functions in PHP

$arr=array();
$arr['one']="one";
$arr['two']="two";
$arr['three']="three";
$newArr=array_keys($arr);
print_r($newArr);
//Array ( [0] => one [1] => two [2] => three )

$arr=array();
$arr[20]="one";
$arr[30]="two";
$arr[40]="three";
$newArr=array_values($arr);
print_r($newArr);
//Array ( [0] => one [1] => two [2] => three )

$arr=array();
$arr[0]="one";
$arr[1]="two";
$arr[2]="three";
function test($v){
  return $v." Hello";
}
$newArr=array_map("test",$arr);
print_r($newArr);
//Array ( [0] => one Hello [1] => two Hello [2] => three Hello )

$arr=array();
$arr[0]="one";
$arr[1]="two";
$arr[2]="three";
$arr1=array();
$arr[3]="taoshihan1";
$arr[4]="taoshihan2";
$arr[5]="taoshihan3";
$newArr=array_merge($arr,$arr1);
print_r($newArr);
//Array ( [0] => one [1] => two [2] => three [3] => taoshihan1 [4] => taoshihan2 [5] => taoshihan3 )
$arr=array("one","two","three");
$arr1=array("4","5","6");
$newArr=array_merge($arr,$arr1);
print_r($newArr);
//Array ( [0] => one [1] => two [2] => three [3] => 4 [4] => 5 [5] => 6 )

$arr=array("2"=>"taoshihan2","1"=>"taoshihan1","3"=>"taoshihan3");
ksort($arr);
print_r($arr);
//Array ( [1] => taoshihan1 [2] => taoshihan2 [3] => taoshihan3 )
使用函数array_search()，搜索某个键值，返回对应的键
$arr=array("2"=>"taoshihan2","1"=>"taoshihan1","3"=>"taoshihan3");
echo array_search("taoshihan1",$arr);
// 1