PHP Syntax and Reasoning with Date If/Else Statement

Question

I am working on a project and I have encountered this code:

$year    = date('Y') - (date('n') > 9 ? 0 : 1);

The way I read it, it seems to be; if the year (2014) minus the month (12) is greater than 9, then the Boolean is False, Otherwise it is true.

However when I go to print the variable, it prints 2014. I then changed 9 to 9000 to see what would happen, and it changed to 2013. I know this sound rudimentary but I can't understand why and I wasn't able to immediately find on google how this makes sense.

EDIT: Sorry, there was a leftover parentheses at the end of the code that wasn't supposed to be there. The code has been edited.

Answer 1

If you change the function calls of date() your code would look like this:

$year    = 2014 - (12 > 9 ? 0 : 1);

Now you may see better that 12 is greater then 9 and it is TRUE! So 0 get's 'used':

$year    = 2014 - 0;

So the result is:

2014

Your adoption is wrong that the ternary operator condition is false!

Answer 2

This looks like a formula for getting the fiscal year. The parenthetical evaluates to 0 if the month is Oct-Dec, 1 otherwise. So it subtracts 1 from the current year unless the date is after Sep 30.

Answer 3

I don't think you noticed the extra paranthesis around the second date parameter.

You're reading the code like this:

date('Y') - date('n')

But, the code actually says:

data('Y') - 1 // or 0 (depending on the returned int from the ternary operation)

Another way to write it is:

$dateX = date('Y');
$dateY = (date('n') > 9 ? 0 : 1);
$result = $dateX-$dateY;
// result will output either 2014 (from $dateX) or 2013 (if $dateY equals 1)

Answer 4

Try it like this.

 $year    = (date('Y') - (date('n')) > 9 ? "false" : "true");
 echo $year; //this will give you false.

Or like this,

 $year    = (date('Y') - (date('n')) > 9 ? 0 : 1);
 echo $year; //this will give you 0.