Type Object in PHP

Question

I’m practicing some code in PHP when I come across this:

<?php
$a = (object) ["a" => "b"];
$b = (object) ["a"  => "c"];

$y = $a <=> $b;
echo $y;
$v=[1,2,3] <=> [1,2,3];
echo $v;
$a= (object) ["a" => "b"];
$b = (object) ["a" => "b"];
echo $a <=> $b;
echo ($y == -1)? 1:0;
?>

Since I haven’t practiced PHP for a long time, my doubts are as follows::

1. Why the exits of the first three echo are being respectively, -1,0,0?

2. How I do this conversion ["a" => "b"] type-to-object?

3. What’s the name of it <=>? comparison operator? Equality? I searched in the php.net I didn’t find anything on that.

Answer 1

Why the exits of the first three echo are being respectively, -1,0,0?

According to the definition of the comparison operator (see below) are the expected results. In the first, the left operand is smaller, i.e., the letter b is smaller than the letter c. In the others the values are identical, therefore the result is 0.

How I do this conversion ["a" => "b"] type-to-object?

Did it the right way, albeit with questionable utility.

What’s the name of it <=>? comparison operator? Equality? I searched on php.net I didn’t find anything on that.

Behold: What are the "Spaceship Operator" <=> of PHP7?.

$a = (object)["a" => "b"];
$b = (object)["a"  => "c"];
$y = $a <=> $b;
echo $y;
$v=[1,2,3] <=> [1,2,3];
echo $v;
$a= (object)["a" => "b"];
$b = (object)["a" => "b"];
echo $a <=> $b;
echo ($y == -1)? 1:0;
var_dump($a);

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.