Addition Issue

[manuka]

Hi I'm having an issue with a piece of code, it pretty much works but the line to output the total weight only seems to be picking up the count and not multiplying it by the weight. Any ideas why this is?

 

Thanks in advance

 

<?php 

mysql_connect("localhost", "*****", "******") or die(mysql_error()); 

mysql_select_db("inventory") or die(mysql_error()); 

$data = mysql_query("SELECT * FROM testDB ORDER BY uid DESC LIMIT 30") 

or die(mysql_error()); 

Print "<p>"; 

while($info = mysql_fetch_array( $data )) 

{ 
$totalweight = ($info['count' * 'itemtype']);

Print $info['count'] . " "; 

Print $info['itemtype'] . " "; 

Print $totalweight . " kgs <br />"; 

} 

Print "</p>"; 

?> 

[Pikachu2000]

What errors are you getting?

[manuka]

According to Firefox's error consol there were a couple of errors with an attached css page but nothing that should affect this

[doddsey_65]

ive never come across your method:

 

$totalweight = ($info['count' * 'itemtype']);

 

but im pretty sure thats not gonna work.

 

Try

 

$totalweight = $info['count'] * $info['itemtype'];

[bspace]

 $totalweight = ($info['count' * 'itemtype']);

Print $info['count'] . " "; 

Print $info['itemtype'] . " "; 

 

take a look at that calculation again

[manuka]

ive never come across your method:

 

$totalweight = ($info['count' * 'itemtype']);

 

but im pretty sure thats not gonna work.

 

Try

 

$totalweight = $info['count'] * $info['itemtype'];

 

With that I get a return of "0"

[btherl]

To explain why it's not working, this is what php thinks:

 

$info['count' * 'itemtype']; # Hmm, multiplying two strings?  I'd better convert them to numbers first
= $info[0 * 0]; # Ok, that makes more sense.  Now simplify
= $info[0]; # Ok now we can look up item 0 in the array (which is indexed by name AND number)
= the count column, which happens to be index 0

[manuka]

Hi btherl, Yeah I can understand enough PHP to get why it doesn't work, however I don't quite know how to get it functioning how I need it to work....

[doddsey_65]

is 'itemType' the weight?

 

have you tried typecasting? Not sure if it would help but its one of the debugging steps i would try

 

$totalweight = ((int)$info['count'] * (int)$info['itemType']);

 

[btherl]

Can you add this code please:

 

print_r($info);

 

and paste the output.

[manuka]

Can you add this code please:

 

print_r($info);

 

and paste the output.

 

Array ( [0] => 1 [count] => 1 [1] => bananas [itemtype] => bananas [2] => 5 [weight] => 5 [3] => 2011-08-23 [created] => 2011-08-23 [4] => 26 [uid] => 26 ) 10 fish kgs
Array ( [0] => 10 [count] => 10 [1] => fish [itemtype] => fish [2] => 10 [weight] => 10 [3] => 2011-08-23 [created] => 2011-08-23 [4] => 25 [uid] => 25 ) 10 weevil kgs
Array ( [0] => 10 [count] => 10 [1] => weevil [itemtype] => weevil [2] => 0 [weight] => 0 [3] => 2011-08-23 [created] => 2011-08-23 [4] => 24 [uid] => 24 ) 10 for kgs
Array ( [0] => 10 [count] => 10 [1] => for [itemtype] => for [2] => 2 [weight] => 2 [3] => 2011-08-23 [created] => 2011-08-23 [4] => 23 [uid] => 23 ) 12 goon kgs 

[btherl]

Thanks.  I think what you want is this:

 

$totalweight = $info['count'] * $info['weight'];

 

Previously you were getting "0" because you were multiplying by $info['itemtype'], which is a string like "bananas".  PHP treats non-numeric strings as "0" in calculations.

 

Also to get a nicer output from print_r() you can do this:

 

print "<pre>"; print_r($info) ; print "</pre>";

 

The pre tags tell the browser to use text formatting instead of html formatting.

[manuka]

Thanks.  I think what you want is this:

 

$totalweight = $info['count'] * $info['weight'];

 

Previously you were getting "0" because you were multiplying by $info['itemtype'], which is a string like "bananas".  PHP treats non-numeric strings as "0" in calculations.

 

Also to get a nicer output from print_r() you can do this:

 

print "<pre>"; print_r($info) ; print "</pre>";

 

The pre tags tell the browser to use text formatting instead of html formatting.

 

Thanks for that, basically I would have been on the right track a lot earlier if I had spotted that is was trying to multiply the wrong variable. Also cheers for the heads up on using the pre tags, that does make the formatting much more user friendly.