Best way to use multiple nested loops

Question

I use php for this, but non-language answers are also welcome.

I have several arrays of objects that I want to program and display in order. Each of the arrays has a different kind of object in them, but all objects have a unique order attribute.

For example:

$people = [{'name':'George','email':'[e-mail]','order':'2'},{'name...];
$sandwiches = [{'type':'bacon','rating':'8/10','order':'1'},{'type...];
$restaurants = ....
$chefs = ...
...

What is the most efficient way to scroll through them?

Assuming I can determine the maximum order, which, I thought, could do something like:

for($i=0; $i< $maximumOrder; $i++)
{
   for($j=0; $j< count($people); $j++)
   {
     if($people[$j]->order == $i)
     {
        //Do the things I want to do
        break;
     }
   }


   for($j=0; $j< count($sandwiches); $j++)
   {
     if($sandwiches[$j]->order == $i)
     {
        //Do the things I want to do
        break;
     }
   }


   for($j=0; $j< count($restaurants); $j++)
   {
   .....


}

But this is not very good, because even if an element with the right order is found in people, it will still continue the cycle through all other arrays. I could just add a boolean to show if the item I need was found (see below), but I'm sure there are better ways to do this.

    for($i=0; $i< $maximumOrder; $i++)
{
   $found = false;

   for($j=0; $j< count($people); $j++)
   {
     if($people[$j]->order == $i)
     {
        //Do the things I want to do
        $found = true;
        break;
     }
   }

   if(!$found == true)
   {
       for($j=0; $j< count($sandwiches); $j++)
       {
         if($sandwiches[$j]->order == $i)
         {
            //Do the things I want to do
            $found = true;
            break;
         }
       }
    }


   if(!$found == true)
   {
       for($j=0; $j< count($restaurants); $j++)
       {
       .....


}

@Victory elseif, while, (, ). , , ( , ), , , , ?

function orderArrayByOrder($a,$b)
{
    return ($a->order < $b->order) ? -1 : 1;
}

$a1 = usort($people, "orderArrayByOrder");
$a2 = usort($sandwiches, "orderArrayByOrder");
$a3 = usort($restaurants, "orderArrayByOrder");


$c1 = count($a1)
$c2 = count($c2)
$c3 = count($c3)

$i1 = 0
$i2 = 0
$i3 = 0


// itertor over order
for ($curOrder ... $maxorder) 
{

   while ($i1 < $c1)
   {
      if($a1[$i1]->order == $curOrder)
      {
        //Do what I need to do
        break;
      }
      elseif($a1[$i1]->order > $curOrder)
      {
        //We know the order won't exist in this array.
        break; 
      }
      $i1++;
   }

   while ($i2 < $c2) 
   {
      if($a2[$i2]->order == $curOrder)
      {
        //Do what I need to do
        break;
      }
      elseif($a2[$i2]->order > $curOrder)
      {
        break;
      }
      $i1++;
   }

}

Answer 1

maxorder, . O(N Log(N)) - , N = max number of elements

• ( php use usort) - O (N log (N))

• maxorder ( ) - O (N)

$a1 = usort($people, function(){})
$a2 = usort($places, function(){})
$a3 = usort($things, function(){})

$c1 = count($a1)
$c2 = count($c2)
$c3 = count($c3)

$i1 = 0
$i2 = 0
$i3 = 0

// itertor over order
for ($curOrder ... $maxorder) {
   // while $a1 is on current order and its index is in bound
   while ($i1 < $c1 && $a1[$i1]->order == $curOrder) {
      echo $a1[$i1]->value;
       $i1++;
   }

   while ($i2 < $c2 && $a2->order == $curOrder) {
      echo $a2[$i2]->value;
      $i2++;
  }
   while ($i3 < $c3 && $a3->order == $curOrder) {
      echo $a3[$i3]->value;
      $i3++;
  }
}

Answer 2

, . O(n), ( , ).

$peopleByOrder = array();
$sandwichesByOrder = array();
$restaurantsByOrder = array();
$uniqueOrderKeys = array();

foreach($people as $person) {
    $peopleByOrder[$person->order] = $person;
    $uniqueOrderKeys[$person->order] = 1;
}

// same for $sandwichesByOrder and $restaurantsByOrder

foreach(array_keys($uniqueOrderKeys) as $oderKey) {

    if(isset($peopleByOrder[$orderKey])) {
      $person = $peopleByOrder[$orderKey];
    }
    else if(isset($sandwichesByOrder[$orderKey])) {
      $sandwich = $sandwichesByOrder[$orderKey];
    }
    else if(isset($restaurantsByOrder[$orderKey])) {
      $restaurant = $restaurantsByOrder[$orderKey];
    }
}