Array confusion

baffled_in_UK

Hi,

This may be quite long so please bear with me 🙂

I have a table that currently has records like this :

area      hits      page
  01        57      index 
  02        01      coach1
  02        01      coach2
  02        01      coach3
  02        03      coach4
  02        01      coach5 
  02        01      coach6
  03        01      clubs1
  03        01      clubs2
  03        01      clubsreg 
  04        01      quiz
  05        01      competition
  08        04      tournaments

What I am trying to do is read this table and create an array that will accumulate the hits of each area and then show a grand total of all hits.

This is what I have done :

<?
// define array
$global=array();

// login to Db
include "getin.php";

// get all records
$result = mysql_query("SELECT * FROM pagehits ORDER BY area",$db);
while ($myrow = mysql_fetch_array($result))  { 
$area = $myrow['area'];
$hits = $myrow['hits'];

// build array
if (!$global[$area]) {
array_push($global, $area);
$global[$area] = $hits;
}else{
$global[$area] = ($global[$area] + $hits);
}
}

// print array
while (list($key, $val) = each($global)) {
echo"$key has a value of $val<BR>";
}

// print total
$total= array_sum($global) ;
echo"The total is:$total"; 

?>

My output looks like this :
0 has a value of 01
01 has a value of 57
1 has a value of 02
02 has a value of 8
2 has a value of 03
03 has a value of 4
3 has a value of 04
04 has a value of 1
4 has a value of 05
05 has a value of 1
5 has a value of 08
08 has a value of 4
The total is:98

The double figure $key values are exactly what I was hoping for, what I don't understand is where all the single figure $key values (in red) have come from.

I've obviously done something wrong or my understanding of PHP arrays is lacking. Can anybody please help ?

Thanks.

bobthedog

Ok - your problem is around the use of array_push... this whole block of code in all: -

if (!$global[$area]) {
    array_push($global, $area);
    $global[$area] = $hits;
}else{
    $global[$area] = ($global[$area] + $hits);
}

Reading the manual tells us that array_push(array, value) is the same as array[] = value - i.e a new integer based key will be created and the value assigned to that, i.e.

$array = array();
array_push($array, "one");
array_push($array, "two");
array_push($array, "three");

.. will leave us with the array

$array[0] = "one"
$array[1] = "two"
$array[2] = "three"

You then seem to apply a string key based assignment - $global[$area] = $hits; - which is assigning a string based key (since the value "01" (or whatever) is string based and not an integer (1), so a new key will be created in this place.

If you followed this all ok then the answer should be fairly obvious - but all you need to do to rectify this is to remove the array_push line. If you try and assign a value to a key in the array which doesnt exist then php will just create it on the fly for you, no need for array_push at all (in this case anyhow). So the rectified code shud probably lok something like: -

if (!$global[$area]) {
    $global[$area] = $hits;
}else{
    $global[$area] = ($global[$area] + $hits);
}

Hope this helps!

baffled_in_UK

Many thanks.

xblue

can't you use SUM in your query? seems a lot easier to me. something like:

$result = mysql_query("SELECT area, SUM(hits) AS hitcount FROM pagehits GROUP BY area");
$total = 0;
while ($myrow = mysql_fetch_array($result))  { 
    echo $myrow['area']." has a value of ".$myrow['hitcount']."<BR>";
    $total += $myrow['hitcount'];
}
echo "The total is: $total";