Try this:

for ($i=0, $k=10; $i<=10 ; $i++, $k--) {
    echo "Var " . $i . " is " . $k . "<br>";
}

The two variables $i and $k are initialized with 0 and 10 respectively. At the end of each each loop $i will be incremented by one ($i++) and $k decremented by one ($k--). So $i will have the values 0, 1, …, 10 and $k the values 10, 9, …, 0.

If, as your code looks like, you have two values running the opposite direction you could simply substract:

echo "Var " . $i . " is " . 10 - $i . "<br>";

But I guess that's not really what you want? Also, be careful with the suggested comma operator. While it is a nice thing it can cause naughty side effects in other languages like C and C++ as PHP implements it differently.

You could also add a condition for the second variable

for ($i=0, $k=10; $i<=10, $k>=0 ; $i++, $k--) {
    echo "Var " . $i . " is " . $k . "<br>";
}

你不应该使用两个for循环来实现你想要实现的目标，因为你总共循环了121次（11x11 ）。 你真正想要的只是在循环之外声明一个跟踪j的计数器，然后在循环中递减j。</ p>

编辑：感谢Gumbo为我捕获包含。< / p>
</ div>

要扩展其他（正确）答案，您所做的就是称为嵌套</ em>循环。 这意味着对于外循环（第一个）的每次迭代，您都在完成整个内循环。 这意味着您可以获得 11 + 11 + 11 + ... = 11 * 11 </ code>输出</ p>
</ div>而不是11个输出

array_map(function($i) {
    echo "Var {$i} is ".(10-$i)."<br/>".PHP_EOL; 
}, range(1,10));

I tried to get a start and end time and store in the database, given a start and end time, you loop through each time using two variables i&j

   $start = "09:00";
   $end = "18:00";
   $strEnTim = strtotime("10.00");

   $slotStart = strtotime($start);
   $slotEnd = strtotime($end);
   $slotNow = $slotStart;

   for( $i=$slotStart, $j=$strEnTim; $i, $j<=$slotEnd; $i+=3600,  $j+=3600) 
   {
        if(( $i < $slotNow) && ( $j < $strEnTim)) continue;
        Slot::create([
            'start_time' => date("H:i",$i),
            'end_time' => date("H:i", $j)
        ]);
   }