PHP在Array中插入值（字母键）

I have array

array (
   a =>  "1",
   b =>  "2",
   c =>  "3"
 )

If I Insert "4" at position "b". old value at position b is move to position "c". and old value at position c is move to position "d".

note position "d" is auto create when Insert value. if key in array is a,b,c,d,e,f,g when Insert value in array, It auto create position "h"

So Result is:

array (
   a =>  "1",
   b =>  "4",
   c =>  "2",
   d =>  "3"
 )

how do I do? Or have some suggestions

Here is addToStack function using array_keys, array_search and array_slice functions:

$arr = array(
    'a' =>  "1",
    'b' =>  "2",
    'c' =>  "3"
);

/**
 * Inserts a new element to stack with offset
 * @param $arr the initial array passed by reference
 * @param $pos string key (position)
 * @param $value inserted value
*/
function addToStack(&$arr, $pos, $value) {
    $keys = array_keys($arr);
    $offset = array_search($pos, $keys);
    $rest = array_slice($arr, $offset);

    $arr[$pos] = $value;
    foreach ($rest as $v) {
        $arr[++$pos] = $v;
    }
}

addToStack($arr, 'b', '4');
print_r($arr);

The output:

Array
(
    [a] => 1
    [b] => 4
    [c] => 2
    [d] => 3
)

This trick may help you.

First of all you need to call the function with array, key and value. In function first check for the key is exist or not. if key exist then store the value, now set the value in array with key and value, find the last key using the end function and then increase the value with one for getting the next character, same if key not exist without storing the value.

$arr = array (
   'a' =>  "1",
   'b' =>  "2",
   'c' =>  "3"
 );

function array_push_user($arr, $key, $val){
    $store = '';
    $bk = '';
    if(array_key_exists($key, $arr)){
        foreach($arr as $keys => $vals){
            if($keys == $key){
                $store = $val;
                $bk = $vals;
                $lst = $keys;
            }else{
                if($bk != ""){
                    $store = $bk;
                    $bk = $vals;
                }
                else
                    $store = $vals;
                $lst = $keys;
            }
            $arr[$lst] = $store;
        }
        $arr[chr(ord($lst)+1)] = $bk;
    }else{
        end($arr);
        $lst = key($arr);
        $arr[chr(ord($lst)+1)] = $val;
    }   
    return $arr;
}



$ret_arr = array_push_user($arr, 'b', '4');
echo '<pre>';
print_r($ret_arr);

Result

Array
(
    [a] => 1
    [b] => 4
    [c] => 2
    [d] => 3
)