Multi-dimensional array reassign value

skeetley

Here is the section of code I am working on.

if (!$link = mysql_connect('localhost', 'user', 'pass'))
    exit("Unable to make a connection to the database");
if (!mysql_select_db("weather_db", $link))
    exit("Unable to select the database"); 

$array = array (); 
$sql = 'ALTER TABLE `All_Wx_2002` ADD INDEX ( `Date_Valid` ) ';
$result = mysql_query ('SELECT `FMFP_ID` , `Date_Valid` , `Time_Valid` , `Temp` , `RH` , `CDir` , `WSpd` , `WGst` , `Rn_1`  FROM All_Wx_2002 WHERE `Date_Valid` > current_date - interval 2 day ORDER BY `Date_Valid` desc, `Time_Valid` desc');

while ($row = mysql_fetch_assoc ($result)) 
{ 
    extract ($row); 
    $array[$FMFP_ID] = array ('Temp' => $Temp, 'RH' => $RH, 'Time_Valid' => $Time_Valid, 'Date_Valid' => $Date_Valid, 'CDir' => $CDir, 'WSpd' => $WSpd, 'WGst' => $WGst, 'Rn_1' => $Rn_1); 
	if ($array[$FMFP_ID][$Temp] == -99.9){$array[$FMFP_ID][$Temp] = "N/A";}
}

Now I only have one record that I made up in the 2 day interval for now, but the Temp is -99.9 I get the -99.9 displayed and there are no spaces in front or after. However, I can't figure out how to get N/A to replace the -99.9!! This seems so simple. Thanks.

leatherback

Hi,

before I dive into your code for -other- potential errors: COud it be that the temp is stored as a strinf instead of a number? Then you have to place quotes aroung the -999 in the if statement..

skeetley

I wondered that too. I change the if to

if ($array[$FMFP_ID][$Temp] == "-99.9"){$array[$FMFP_ID][$Temp] = "N/A";}

and it still didn't work. I even tried as a test:

if ($array[$FMFP_ID][$Temp] == -99.9){$array[$FMFP_ID][$Temp] = 10;}

and that didn't work either. In both cases I still see -99.9 displayed.

skeetley

The problem seems to be that $array[$FMFP_ID][$Temp] is empty when I do the compare in the if statement. I threw in echo $array[$FMFP_ID][$Temp]; as you can see below before the compare and it brings back nothing, while if in the same place I put in a echo "something"; it displays that. How will be the best way to tackle error checking then?

while ($row = mysql_fetch_assoc ($result)) 
{ 
    extract ($row); 
    $array[$FMFP_ID] = array ('Temp' => $Temp, 'RH' => $RH, 'Time_Valid' => $Time_Valid, 'Date_Valid' => $Date_Valid, 'CDir' => $CDir, 'WSpd' => $WSpd, 'WGst' => $WGst, 'Rn_1' => $Rn_1); 
	echo $array[$FMFP_ID][$Temp];
	if ($array[$FMFP_ID][$Temp] == -99.9){$array[$FMFP_ID][$Temp] = -55.5;}
}

leatherback

Haha, now I think i've spotted the icky thing:

You use a variable in your array-key. So if you state:
if ($array[$FMFP_ID][$Temp]
it is actually looking in the if ($array[$FMFP_ID]['whatever value $temp has'].

So you should use:
if ($array[$FMFP_ID]['Temp'].

Makes me think wether you are doing the same with $FMFP_ID..? Is this a name, or do you want the value of a variable in there?

Out of curiosity.. Why ar you placing things in arrays there?

skeetley

Thanks leatherback, everything is working great now. I knew it had to be something simple that I was overlooking.

Why am I using arrays here? Because it is the only way I can think of to go. I have a database that is updated hourly with a weather report for about 100 stations. By the end of the year this db has about a million records in it. I then have a map where if you mouseover the station, the latest observed conditions pop up. If you click on that portion of the the map, you can get the past 24 hour conditions and such. By using my array here I can simply put stuff like $array['CNDLK']['Temp'], or $array['CNDLK']['RH'] into my mouseovers and have the latest data get displayed. I am still working on some aspects of the 24 hours data and such, but this array system works better than making a sting for each variable. I hope that satisfies your curiousity. Thanks for your help!