[SOLVED] Count and multidimensional arrays

[SchweppesAle]

hi, I have the following code

 

for($i = 0; $i < count($update); $i++)			
		{



		}	

 

$update[$i][$y] is a two dimensional array, the count function will return the number of values $i however I'd like to add an additional statement which will pull the "highest pointer" [$y] so that I can test each of the [$y] pointers for dimension [$i].

 

I hope that makes sense.  Basically, I'm storing an id value within the pointer itself.  I need to run  a check on each element of the array then update the database should the value associated with that pointer(which is also an id within the database) is different from what's already in there.

[Bendude14]

for($i = 0; $i < count($update); $i++)         
{
    for($j=0; $j < count($update[$i]); $j++
    {
          //check here using $update[$i][$j]

    }             
            
         
}   

[ignace]

We'll need some more information or some sample data, maybe this helps?

 

$highestPointer = 0;
$sizeOf = sizeof($update);
for ($i = 0; $i < $sizeOf; ++$i) {
    $pointer = max($update[$i]);
    if ($pointer > $highestPointer) {
        $highestPointer = $pointer;
    }
}

[Psycho]

I would advise not using count($array) within a for() loop for two reasons:

 

1. The foreach operator was designed for arrays

2. The for loop has to continually calculate the size of the array on each iterration. When using a for loop it is more efficient to define a value before the loop instead of recacluating each time (there are exceptions to this).

 

Anyway, this is how I would handle this:

 

foreach($update as $subarray)
{
    foreach ($subarray as $value)
    {
        //$value = $update[$i][$j] from your initial example
    }
}

[thebadbad]

To supplement mjdamato; if you also want to have access to the keys, use as key => value:

 

foreach($update as $i => $subarray)
{
    foreach ($subarray as $j => $value)
    {
        //$value = $update[$i][$j] from your initial example
    }
}

[SchweppesAle]

ok, here's an example

 

array[1][24] = micro;

array[2][40] = soft;

array[3][35] = blows;

 

The id for each of these items would be stored within the second bracket.  so there's an entry within the database with an id of 24 which may/may not be micro.  The problem isn't so much retrieving the element with the highest value, but rather the highest pointer. 

 

if($update != NULL)	
{		



		for($i = 0; $i < count($update); $i++)			
		{
			for($j = 0; $j < max($update[$i]); $j++)
			{
				if($update[$i][$j] != NULL)
				{
					$updating = 'works';
				}
			}



		}	

}

 

Unfortunately, the above code will pull the highest value $y for that array. 

[SchweppesAle]

To supplement mjdamato; if you also want to have access to the keys, use as key => value:

 

foreach($update as $i => $subarray)
{
    foreach ($subarray as $j => $value)
    {
        //$value = $update[$i][$j] from your initial example
    }
}

 

lol, wait that's a good idea.  I'll try that then

[SchweppesAle]

you're the man, I didn't know you could access the keys like that with a foreach. 

 

Thanks though, this was just what i needed.