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Posted by Erwin Moller on 11/06/06 16:06
brett wrote:
>> if ((is_page()) || ($category->cat_ID === $cat) ) {
>
> What is the notation for equivalency? Is it "==" or "==="?
== is more loose than ===
=== also checks if the data compared is of the same type.
eg
$a = 1;
$b = "1";
if ($a == $b){
// evaluates to true
}
if ($a === $b){
// evaluates to false
}
This can be a very important extra = in some situations. :-)
A common situation where === makes sense is a functioncall that can return 0
as valid answer, eg:
// This function returns the number of elements in an array
// or it returns false if not an array is passed
function countNumber($someArray){
if is_array($someArray){
return count($someArray);
} else {
return false;
}
}
Now if you use this function and feed the following 3 variables to it:
$test = array("bla",3,24);
$result = countNumber($test);
if ($result){
echo "number of elements $result";
} else {
echo "Not an array!";
}
That works ok, it returns 3.
suppose $test was:
$test = 23;
Which is also ok, it would respond that $test is not an array.
Now the problem:
$test = array();
If you feed this, PHP will correctly count 0 elements, and thus return 0.
However, when used as an expression, 0 evaluates to false, thus PHP will
incorrectly say it was not an array.
If you use the following construct, this will NOT happen.
if ($result === true){
echo "number of elements $result";
} else {
echo "Not an array!";
}
Regards,
Erwin Moller
>
> Thanks,
> Brett
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