Hide output if variable don't have data PHP [duplicate]

Question

I made this:

 global $product;
 $koostis = $product->get_attribute( 'color' );

 echo "<h2>Color: ".$koostis."</h2>";

This show a color attribute on my product.

But if a product don't have a color attribute this script show only: "Color:" of course.

I try to use:

if (isset($koostis)) {
echo "<h2>Color: ".$koostis."</h2>";
}

But don't work because the variable is not exactly empty, i need a method to hide echo "<h2>Color: ".$koostis."</h2>"; if the variable not contain data.

Exist?

Answer 1

If the variable is blank, you can check for that with empty:

if (!empty($koostis)) {
    echo "<h2>Color: ".$koostis."</h2>";
}