php - 基于范围键返回数组

Question

I have an array with of enumerating numbers, like:

$pageNumbers = array(1,2,3,4,5,6,7,8,9,10);

Now I have an active page number $currentPage and want to have based on this, before and after 2 elements - a total number of 5.

$currentPage = 2:

Return: array(1,2,3,4,5)

$currentPage = 6

Return: array(4,5,6,7,8)

$currentPage = 10

Return: array(6,7,8,9,10)

Unfortunately, I did not come up with an elegant and simple method to solve this (2x while, 1 big foreach and so on). Maybe you have an idea.

My first idea was:

foreach ($pageNumbers as $page) {
        if($page < $currentPage+3 && $page > $currentPage-3) {
            array_push(...);
        }
    }

This will work for the $currentPage = 6, but if $currentPage = 1, it will only return 1,2,3.

Answer 1

Use array_slice and cut out the part of the array you need.

I use an if to see where to slice the array.

if($currentPage < 3){
    $arr = array_slice($pageNumbers,0,5);
}elseif($currentPage > count($pageNumbers)-2){
    $arr = array_slice($pageNumbers,-5,5);
}else{
    $arr = array_slice($pageNumbers,$currentPage-3,5);
}

See working example below.
https://3v4l.org/fpOFQ