Thanks for reading this

I have this function that based on the local currency of the user ($currency_to) and currency the data is being quoted in, currently fixed as CNY ($currency_from), uses the yahoo finance currency calculator to take a number ($figure) and spit back either:

a) The value in the currency it is being displayed in

return round($exchange_rate*$figure, -1) . ' ' . $currency_to;

or

b) if the value is quoted as 0 or nothing (null) it supposed to notify the user that its not applicable

 return "N/A";

The problem is that it does not care if the value is 0 or null, it just gives the value in the (a) format i.e. 0 USD

Here is the function:

<?php

function display_price ($currency_from, $currency_to,$figure ) {
$url = "http://quote.yahoo.com/d/quotes.csv?s="
. $currency_from . $currency_to . "=X"
. "&f=l1&e=.csv";
$open = fopen($url, "r");
$exchange_rate = fread($open, 2000);
fclose($open);

if ($exchange_rate == "0.00")
   $exchange_rate = "1";
else
$error = "sorry, we could not determine your location and display the prices in your local area,";


if ($figure=="null")
  return "N/A";
else if ($figure=="0")
  return "N/A";
else
  return round($exchange_rate*$figure, -1) . ' ' . $currency_to;  

}
$currency_from="CNY";?>

Also including the bit where it is being spat back, though I am pretty sure the problem is with the function.

<?php
mysql_connect($server,$user,$password);
@mysql_select_db($database) or die("Sorry, unable to select database");
$result = mysql_query("SELECT * FROM drup_content_type_school ORDER BY field_schoolname_value");
$i=0;
 while($row = mysql_fetch_array($result))
  {
if ($i % 2)
   $class= "tr3";
else 
  $class= "tr2";
  echo "<tr class='" . $class . "'>
<td class='td1'><a href='http://compare-chineselanguageschools.com/content/output-school?school=" . $row[field_schoolname_value] . "'>" . $row['field_schoolname_value'] . "</a></td>
<td class='td2'>" . $row['field_est_value'] . "</td>
<td class='td3'>" . $row['field_max_class_size_value'] . "</td>
<td class='td1'>" . display_price($currency_from, $currency_to, $row[$price]) . "</td>
<td class='td1'>" . $row['field_max_class_size_value'] . "</td>
</tr>
";
$i++;
}

  ?>

Thank you so much for any input.

a null value is never going to be == "null", you should use is_null().

If you need to evalute null OR 0, the expression would look like this:

PHP Code:

if(is_null($figure) || $figure === 0) {
    return 'N/A';
} 


A simple !$figure should also suffice, though I think my example is more readable.

Hi wayfarer07,

you are star, helped me out twice now with the same site,

very very thankful

A better catch-all would be to use empty because it would evaluate true for NULL, false, 0 or empty string values (including spaces or new lines).

if (empty($figure)) return 'N/A';

true, empty() is very useful like that, and it includes the value of 0, or even an empty array() or an empty string "".

thanks for the help guys,

i ran into another little hick up further down the road and the empty() solved that.


its fantastic that there are people on the net that so readily share their knowledge, few other places in society where people help completely random strangers.

Originally Posted by wayfarer07

a null value is never going to be == "null"

If you want to stick with that, just make it $var==null, with no quotes.