Zeros being read as null values

[synergy]

I'm trying to submit a series of fields to the database, while checking to make sure those fields have data input into them. Everything works unless I input a '0' into any of the fields. It seems as if it is being read as a null value flagging the error trapping code:

if ((!$sel_dbname) || (!$sel_type) || (!$sel_size) || (!$sel_papertype) || (!$sel_colorsfront) || (!$sel_colorsback) || (!$sel_pixelwidth) || (!$sel_pixelheight) || (!$sel_cropneeded) || (!$sel_croppedwidth) || (!$sel_croppedheight) || (!$sel_viewwidth) || (!$sel_viewheight)) {
echo "<p class=\"contentheader\">Add Product</p>
<div class=\"content2\">You are missing required information.<br><br>
Go back and try again.</div>";

The fields are varchar. Any ideas why the 0's wont go thru?

[WinterDragon]

hrm, I tried this...

function numCheck($number) {
if($number == 0) {
return 1;
} elseif($number == "" || $number == NULL) {
return 0;
}}

Not that great of a function but it works...

hrm anyways

if(numCheck($number)) {
echo "Its not TOTALLY empty, and its not NULL....";
}

It works... maybe you can think of a better way, I'm at work lol

[synergy]

Is this code:

if (!$var) {
// echo error
}

the same as this code?

if ($var == "") {
// echo error
}

[WinterDragon]

yeah I was just being retarded... 😉

[synergy]

$var = "0";
if (!$var) {
echo "<div class=\"content2\">Error 1!</div>";
}
if ($var == "") {
echo "<div class=\"content2\">Error 2!</div>";
}
echo "<div class=\"content2\">Worked!</div>";

The result of this code says:

Error 1!
Worked!

So Error 2 did not happen. If (!$var) and ($var == "") is the same why is a value of 0 throwing the error?

[Weedpacket]

If you're wanting to see if a variable contains a value, you can use [man]empty[/man]. If you want to specifically check that it's non-null, (as opposed to non-0 or non-""), then you can use the type-safe comparison operators === and !==. These don't do any typecasting, so if the argument on the left of a === comparison is (say) an integer, and the argument on the right is a string, then the result is false, even if the integer is 0 and the string is "0".

Even though 0==null and "0"==0, "0"!=null, because PHP's typecasting rules would turn those comparisons into, respectively, 0==0, "0"=="0", and "0"!=""

echo (0=="0")?'0=="0"':'0!="0"';
echo '<br>';
echo (0=="")?'0==""':'0!=""';
echo '<br>';
echo ("0"=="")?'"0"==""':'"0"!=""';
echo '<br>';
echo (0==$oink)?'0==$oink':'0!=$oink';
echo '<br>';
echo (0==null)?'0==null':'0!=null';
echo '<br>';
echo (0===null)?'0===null':'0!==null';
echo '<br>';
echo ($oink===null)?'$oink===null':'$oink!==null';
echo '<br>';
echo (0==="0")?'0==="0"':'0!=="0"';
echo '<br>';
echo ("0"==null)?'"0"==null':'"0"!=null';
echo '<br>';
echo ("0"===null)?'"0"===null':'"0"!==null';
echo '<br>';

0=="0"
0==""
"0"!=""

Notice: Undefined variable: oink in test.php on line 8
0==$oink
0==null
0!==null

Notice: Undefined variable: oink in test.php on line 14
$oink===null
0!=="0"
"0"!=null
"0"!==null

[laserlight]

empty() probably shouldnt be used in this case, it returns true for both null values and zero values, which can be handy at times but isnt what you want here.

The reason for the error when using !$varname directly would be that !0 is 1, or true.

Might want to use isset() or perhaps use what weedpacket suggested.
There's also is_null(), but I think that might not be applicable here, not so sure though.