If Then Else

johnberman

Hi so this does not work

if ($gender = "1") {
$sex = "male";
} elseif ($gender = "2") {
$sex = "female";
}

If gender is 2 $sex is always male ?

Sure its a syntax thing

Regards

John B

laserlight

You mixed up = and ==

johnberman

thanks, can you explain a little more as im not getting it

Regards

John B

NogDog

"=" is for assigning the value on the right to the thing on the left.

"==" is for comparing the values of the things on either side.

"===" is for comparing the value and type of the things on either side.

Therefore, since you presumably want to do comparisons in your if/elseif tests, you probably don't want to use "=". (There are situations where you might, however, if you want to base what happens next based on the result of an assignment.)

johnberman

Thanks

John B

sneakyimp

I would strongly recommend doing some quick experiments to see how this works in any particular circumstance.

In particular check this out:

		$i = 1;
		var_dump($i == 9999);
		var_dump($i = 9999);

The first var_dump statement outputs false because the value assigned to $i is 1, not 9999. The second var_dump statement outputs the integer 9999 because you are assigning this value to $i because there is only one equal sign. The vast majority of the time, you want to use at least two equal signs with your if statement because you are asking if the two values are equal and you are not making a value assignment. There are a few exceptions.

This is also worth noting:

		$i = 1;
		var_dump($i == "1");
		var_dump($i === "1");

The first var_dump returns TRUE because PHP performs an implicit cast of the values for the sake of comparison. The second one is false because $i is an integer value but "1" is a string value. As Nogdog said, when you use 3 equal signs (===), you are testing both the values and their native type. This is called 'strict equality.'

laserlight

sneakyimp wrote:
when you use 3 equal signs (===), you are testing both the values and their native type. This is called 'strict equality.'

The PHP manual calls it "identical" and so we might say "identity". Calling it "strict equality" is probably not a good idea since in the context of comparisons, "strict" usually refers to a relation that is not reflexive, but equality is reflexive.

Weedpacket

laserlight wrote:
The PHP manual calls it "identical" and so we might say "identity".

And when being used to compare objects it really does test for "object identity" - i.e., that its operands are both references to one and the same object.

sneakyimp

Thanks for the clarifications. Perhaps it was just me that was misusing the term 'strict' in this case. It might be due to the naming of the 3rd parameter of functions like [man]in_array[/man].