Question: I have three variables:

```
$var1
$var2
$var3

```

I'm actually looking for the best way to check if **only one** of these three variables is not empty and the **two others** are empty.

Is that possible to do this with one `if` only? If not, then what's the best way?

The variables all contain text.

Answer: 
```
$counter=0;
$counter+= empty($var1) ? 0:1;
$counter+= empty($var2) ? 0:1;
$counter+= empty($var3) ? 0:1;

if($counter==1)
   echo "Exactly 2 are empty";

```

**[Fiddle](https://eval.in/641962)**

Or you can simply do

```
var_dump(count(array_filter(array($var1,$var2,$var3)))==1);

```

**[Fiddle](https://eval.in/641979)**
Bitwise XOR is great for this:

```
$var1 ^ $var2 ^ $var3

```

You *might* have trouble if the variables don't cast to boolean easily, in which case you'd need to do `empty($var)` on each of them.

Boom. Zero `if`s.

**Update**

Oops, if they are *all* not empty, true ^ true ^ true == true

You'll need to check against all of them being true:

```
($var1 ^ $var2 ^ $var3) && !($var1 && $var2 && $var3)

```