Array help - detect "Undefined offset" ?

[benphp]

I have something that looks like this:

<?php
for ($i=0;$i<=$rowcount;$i++) { 
$sum = $rows[$i];
}
?>

 

But the $rowcount isn't always the same, therefore I get the Undefined offset error. Is there a function that can determine if the offset will be undefined before it attempts the loop? Otherwise, I'll need to write more lines to an already large page.

 

Thanks!

[kenrbnsn]

do

<?php
$sum = 0;
$rowcount = count($rows);
for ($i=0;$i<$rowcount;$i++)
    $sum += $rows[$i];
?>

 

Ken

[CroNiX]

As kenrbnsn pointed out, you need to use < not <=.  The reason is count() will start counting at 1 but arrays start at 0, so it will never be equal to which is why you get the error.  It is looking for an index 1 greater than the actual size of the array when you have the =.

[benphp]

The issue is a bit more complicated - I simplified it for the question, but here is the actual code. Maybe one of you wizards can figure this one out. The trick is that $colcount may be greater than the elements in the $rows array, because the elements in the $rows array varies:

 

<?php
for ($x=0;$x<=$colcount-1;$x++) {  
print "<td>";
$sum = 0;
for ($i=0;$i<=$rowcount-1;$i++) { //cycle through the row array
	//$rows [row] [column] 
	$sum = $sum + $rows[$i][$x];
	$avg = round($sum / $rowcount, 2);
}
print $avg;
print "</td>";
}
?>

 

 

[PFMaBiSmAd]

Use a foreach() loop, it iterates over each element in an array and it does not care what the indexes are or how many of them there are.

[discomatt]

Alternately, use an isset() call.

 

for ($i=0;$i<=$rowcount;$i++)

if ( isset($rows[$i]) )

$sum = $rows[$i];

[benphp]

The isset works!

 

When I try a foreach on $rows, it doesn't work as I expect - probably because I don't understand the multidimensional array and how it works.

 

foreach ($rows as $temp) {

 

provides lots of "Illegal offset type" errors.

[sasa]

can you print_r($rows); and post output