Question

How to reverse subarray of an array in PHP

Answer 1

function reverseSubarray(&$arr, $start, $end) {
    if ($end > count($arr)) {
        echo "End index out of range";
        return;
    }
    
    $mid_sub = ($end - $start + 1) / 2;  
        
    for ($i = 0; $i < $mid_sub; $i++) {
         $tmp = $arr[$start + $i];
         $arr[$start + $i] = $arr[$end - $i];
         $arr[$end - $i] = $tmp;      
    }
}
  
  
$arr = array(1, 4, 8, 0, 7, 3, 9, 5, 6);
           
$start = 2;
$end = 6;
           
reverseSubarray($arr, $start, $end);
    
print_r($arr);


    
    
/*
run:
    
Array
(
    [0] => 1
    [1] => 4
    [2] => 9
    [3] => 3
    [4] => 7
    [5] => 0
    [6] => 8
    [7] => 5
    [8] => 6
)

*/

 

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