array_walk()与array_map()

array_walk()

函数可以通过一个回调函数来遍历一个数组,回调函数作用于每一个数组元素;它的返回值是true/false

1.遍历数组
$nums = array("one","two","three");
array_walk($nums,function($item,$index){
echo $item.$index;
});


2.更改元素
$nums = array("one","two","three");
array_walk($nums,function(&$item,$index,$prefix){
$item = "$prefix-$item";
},'number');

更改元素,使用&;当回调函数需要第三参数,需要接收,并在array_walk传递第三个参数

array_map()

函数可以通过一个回调函数来遍历/返回一个新数组,回调函数作用于每一个数组元素;它的返回值是一个新数组

1.更改元素
$nums = ["one","two","three"];
$numsb = array_map(function($item){
return $item."is num";
},$nums);


2.并行合并/更改数组
$nums = ["one","two","three"];
$numsb = ["a","b","c"];
$newar = array_map(null,$nums,$numsb);
//[["one","a"],...]


// 更改合并
$nums = ["one","two","three"];
$numsb = ["a","b","c"];
$newar = array_map(function($a,$b){
return $a." is ".$b;
},$nums,$numsb);
//["one is a","two is b"]