while loop within a loop problem?

[mitwess]

so i have some code with a while loop which was working fine

 

$l=0;
$lx=f.$l;



$j=1;
while ( $j<500 ) {

$query = "SELECT id, fb_user_id, friend_id, f0 FROM sim_rp WHERE id ='".$j."'  ";
$rs = mysql_query($query);
$row = mysql_fetch_array($rs, MYSQL_ASSOC);
$id1 = $row['fb_user_id'];
$id2 = $row['friend_id'];


$query = "SELECT $lx from users  where fb_user_id ='".$id1."' ";
$rs = mysql_query($query);
if (mysql_num_rows($rs) > 0) {
$row1 = mysql_fetch_array($rs, MYSQL_NUM);
$compare1[$j] = $row1[0]; 
}

$query = "SELECT $lx  from users where fb_user_id ='".$id2."' ";
$rs = mysql_query($query);
if (mysql_num_rows($rs) > 0) {
$row2 = mysql_fetch_array($rs, MYSQL_NUM);
$compare2[$j] = $row2[0]; 
}






++$j;
}


//To find the correlation of the two arrays, simply call the 
//function Correlation that takes two arrays:

$correlation = Correlation($compare1, $compare2);
$correlation = round($correlation,3);

//Displaying the calculated Correlation:
//print $correlation;

//The functions that work behind the scene to calculate the
//correlation

function Correlation($arr1, $arr2)
{       
    $correlation = 0;
   
    $k = SumProductMeanDeviation($arr1, $arr2);
    $ssmd1 = SumSquareMeanDeviation($arr1);
    $ssmd2 = SumSquareMeanDeviation($arr2);
   
    $product = $ssmd1 * $ssmd2;
   
    $res = sqrt($product);
   
    $correlation = $k / $res;
   
    return $correlation;
}

function SumProductMeanDeviation($arr1, $arr2)
{
    $sum = 0;
   
    $num = count($arr1);
   
    for($i=0; $i<$num; $i++)
    {
        $sum = $sum + ProductMeanDeviation($arr1, $arr2, $i);
    }
   
    return $sum;
}

function ProductMeanDeviation($arr1, $arr2, $item)
{
    return (MeanDeviation($arr1, $item) * MeanDeviation($arr2, $item));
}

function SumSquareMeanDeviation($arr)
{
    $sum = 0;
   
    $num = count($arr);
   
    for($i=0; $i<$num; $i++)
    {
        $sum = $sum + SquareMeanDeviation($arr, $i);
    }
   
    return $sum;
}

function SquareMeanDeviation($arr, $item)
{
    return MeanDeviation($arr, $item) * MeanDeviation($arr, $item);
}

function SumMeanDeviation($arr)
{
    $sum = 0;
   
    $num = count($arr);
   
    for($i=0; $i<$num; $i++)
    {
        $sum = $sum + MeanDeviation($arr, $i);
    }
   
    return $sum;
}

function MeanDeviation($arr, $item)
{
    $average = Average($arr);
   
    return $arr[$item] - $average;
}   

function Average($arr)
{
    $sum = Sum($arr);
    $num = count($arr);
   
    return $sum/$num;
}

function Sum($arr)
{
    return array_sum($arr);
}

 

 

but when i try to add an additional while loop around the whole thing, it doesn't work.  any idea on why?  or a work around

 

 

when i add the following to the beginning of the above code (after $l =0;)

 

while ( $l<50 ) {

 

and this to the end of the above code (because i want to iterate the value of $l)

 

++l;
}

 

the script stops working.  any ideas?

 

[ChemicalBliss]

++l;

 

should be $l++;

 

-CB-

[sasa]

close loop before declaration of functions

[mitwess]

the missing $ was a transcription error.  can i not have a function within a loop?  i really need it to be within the loop for what i'm trying to do.

[ChemicalBliss]

No you cannot redeclare functions (so the while loop would fail anyway).

 

But, there is a slightly complicated work-around:

 

you can do this:

<?php

$function_prefix = "func_";

$i = 0;

$funcname1 = create_function('$arg1,$arg2','return $arg1." - ".$arg2;');
echo($funcname1("hello","world")."<br />");

$funcname2 = create_function('$arg1,$arg2','return $arg1." - ".$arg2;');
echo($funcname2("hello","world"));


?>

 

 

Good Luck

-CB-

[teynon]

I dont know why you would ever need to declare a function inside of a loop. You should rethink your logic there.

[mitwess]

well i have two sets of 20 database fields, each with @2000 records

 

i wanted to compare each pair (loop one)  for each field (loop two)

 

loop one is two related records being grabbed from one of the 20 database fields, one at a time, 2000 times.

 

loop two causes everything to happen again for the next iterative db field (++$l)

 

the function to determine correlation needs to happen after loop one, when two sets of 2000 records have been loaded into an array for the correlation function, and then the process needs to restart (++$l) with the analysis if the next db field

 

obviously i need to be doing it differently since my current design doesn't work, that's why i posted the question.  i can't figure out another way to do it at present.

[ChemicalBliss]

Maybe if you explain what your data is, and exactly your planning to do with the data, we can provide the logic you need .

 

Then you can code it .

 

-CB-