Spaceship Operator

https://stackoverflow.com/questions/30365346/what-is-the-spaceship-operator-in-php-7#30365399

The <=> ("Spaceship") operator will offer combined comparison in that it will : 

Return 0 if values on either side are equal
Return 1 if the value on the left is greater
Return -1 if the value on the right is greater

The rules used by the combined comparison operator are the same as the currently used comparison operators by PHP viz. <, <=, ==, >=and >. Those who are from Perl or Ruby programming background may already be familiar with this new operator proposed for PHP7. 

   //Comparing Integers

    echo 1 <=> 1; //output  0
    echo 3 <=> 4; //output -1
    echo 4 <=> 3; //output  1

    //String Comparison

    echo "x" <=> "x"; //output  0
    echo "x" <=> "y"; //output -1
    echo "y" <=> "x"; //output  1