PHP在Array中插入值（字母键）

Question

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

Answer 1

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
)