php - while loop is itering double the times expected and nested for loop is iterating 1.5 times more than expected

Question

This script is supposed to to get a multidimensional array and iterate through the values.

The array size is 10 and each element should contain an associative array:

$games[0] => array('foo' => 'bar')
$games[1] => array('foo1' => 'bar1')
etc..

The while loop should iterate 5 times in this example. The for loop should iterate 10 times for each iteration of the while loop.

So I am expecting the echo to be:

countwhile = 5 countfor = 50 totalgames = 50

but im actually getting

countwhile = 5 countfor = 150 totalgames = 150

I believe $games array is not the problem because i have have made that call below before and have used print_r to view the contents and it is as expected.

This whole code is not in a function or class just as is on my index.php page, could the problem be to do with the variable scopes?

$totalruns = 5;  
$endindx = 10;
$startindx = 0;
$countwhile = 0;
$countfor = 0;
$totalfilesize = 0;
$totalgames = 0; 
$sizeof = 0; 

while($totalruns > 0)  
{  
     $games = $feedHandler->getGames($startindx, $endindx);  
     $sizeof = sizeof($games);  

     for($i=0; $i<$sizeof; $i++)  
     {  
          $totalfilesize += $games[$i]['swf_file_size'];
          $countfor++;  
     }  

     $startindx += 10;
     $endindx += 10;  
     $totalruns -= 1;  
     $totalgames += $sizeof;
     unset($games);  
}  

echo'<p>' . ' countwhile = ' . $countwhile . ' countfor = ' . $countfor . '</p>';

Holy obfuscated code. It may help to give yourself meaningful variable names instead of the alphabet. And sizeof is an alias of count(), FYI. I'm playing around with it now, but see if you can clean that up in the mean time (you'll probably get more willing people to assist you). — Brad Christie
– Brad Christie, Commented Dec 30, 2010 at 16:13
why do you set $sizeof = sizeof($games) at every for iteration? you could do a count before the loop, you could even use $e as you overwrite $e at every loop (so the last $e += $e is useless) — regilero
– regilero, Commented Dec 30, 2010 at 16:15
I have edited thia post with the updated code, given all vars meaningful names. — Anish
– Anish, Commented Dec 30, 2010 at 17:12
Can anyone explain why $countfor and $totalgames are 150 instead of 50? I have tried this loop again without unset($games) and get the same result, when I print_r($games) I get an array with 50 elemenets as expected. — Anish
– Anish, Commented Dec 30, 2010 at 17:14

ajreal · Accepted Answer · 2010-12-30 16:20:48Z

3

problem 1:

$sizeof = sizeof($games)-1;

explain 1:

for($i=0, $sizeof = sizeof($games);$i<=$sizeof;$i++)

the above will execute 11 times is the sizeof($games) is 10
So, either

for($i=1, $sizeof = sizeof($games);$i<=$sizeof;$i++)  

or

for($i=0, $sizeof=sizeof($games)-1;$i<=$sizeof;$i++)

problem 2 :

$e = sizeof($games);

explain 2 :

$e = count($games);  
...
$e += $e;

If the final size of $games is 50, you just sum it to 100
so, it some kind of logic problem

edited Dec 30, 2010 at 16:20

answered Dec 30, 2010 at 16:13

ajreal

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Comments

Brad Christie · Accepted Answer · 2010-12-30 17:34:09Z

I know the answer has been accepted, but thought I'd refactor and make this a little more clean.

function retrieveGamesInfo($limit, $start = 0)
{
  $feedHandler = new FeedHandler(); // ignore this, just for testing to simluate your call

  if ($start > $limit)
    throw new Exception("Start index must be within the limit");

  $result = Array(
    'TotalGames' => 0,
    'TotalFileSize' => 0
  );

  // iterate over the results in groups of 10
  $range = $start;
  while ($range < $limit)
  {
    $range_end = $range + 10; // change me to play with the grab amount
    if ($range_end > $limit)
      $range_end = $limit;

    // grab the next 10 entries
    $games = $feedHandler->getGames($range,$range_end);

    $result['TotalGames'] += count($games);

    foreach ($games as $game)
      $result['TotalFileSize'] += $game['swf_file_size'];

    $range = $range_end;
  }
  return $result;
}
var_dump(retrieveGamesInfo(50));

based one everything I've read and taken in, this should be a good supplement. The above provides the following result:

array(2) {
  ["TotalGames"]=>
  int(50)
  ["TotalFileSize"]=>
  int(275520)
}

regilero · Accepted Answer · 2010-12-30 16:18:57Z

0

As i said in my comment $e is overwritten at each loop, so what you have in $e at the end is just the last count of elements in $games *2. Added with ajreal issues this means results are what your code is expected to render :-) and I'm quite sure your last $game is not just 10 elements but 50. Quiet sure... but it's hard to read.

answered Dec 30, 2010 at 16:18

regilero

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2 Comments

regilero Over a year ago

well, I would say WE were right and you were wrong several times :-)

markus Over a year ago

just because this correct answer solved your immediate problem I don't think it should be the accepted answer. just solving the immediate problem doesn't make this code any better!

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