Question

echo empty($location);
switch($location){
    case (empty($location)):
expression 1;
    break;
    case ($location%10000==0):
expression 2;
    break;
    case ($location%100==0):
expression 3;
    break;
    default:
    expression 4;
    break;

}

When I echo empty($location), it prints out 1, why is expression 1 not executed?

Answer 1

You’re not using switch statements properly. The way they work is to compare each case value against the initial switch value.

In your case, let’s pretend $location = null;

echo empty($location);    // true: null is considered empty.

switch ($location) {
    case empty($location) :    // this performs the check:
                               // $location == empty($location)
                               //      null == true ==> false

so that’s why it doesn’t run..

I’d recommend sticking to if .. else in this case.