for循环中的php undefined offset

Question

This has baffled me for quit a while. I want to compare my data with the data coming next to determine when to change the row.

<?php
    $seasons; // laravel eloquent model from controller  
    $i = 0;
    $max = count($seasons);

    for($i; $i<$max; $i++):
        $x = $i+1;
        print_r($seasons[$i]);  // ok 
        print_r($seasons[1]);   // ok 
        print_r($seasons[0+1]); // ok 
        print_r($seasons[$x]);  // undefined  
        print_r($seasons[$i+1]); // undefined 
    endfor;
?>

Answer 1

<?php
    $seasons; // laravel eloquent model from controller  
    $i = 0;
    $max = count($seasons);

    for($i; $i<$max; $i++):
        $x = $i+1;
        print_r($seasons[$i]);  // ok 
        print_r($seasons[1]);   // ok 
        print_r($seasons[0+1]); // ok 
        if(isset($seasons[$x])){
            print_r($seasons[$x]);  // undefined  
        }
    endfor;
?>

By the way, $x and $i+1 these both lines are same. because $x = $i + 1; and again you are doing $i + 1.