array_filter、array_walk、array_map的区别

1. <?php
2. $arr=array(
3. 1,2,3,4,5,6
4. );
5. function filter($var){
6. if($var%2==0)
7. return true;
8. }
9. $data=array_filter($arr,"filter");
10. $data=array(2,4,6);
11. ?>

1. <?php
2. $arr1=array('linux','Php','JAVA');
3. array_map('strtoupper',$arr1);
4. ?>