PHP min and max with array, is it reliable?

Question

This works but, is it reliable? Will it always work since the MAINarray is containing ANOTHERarray which contains 2 values and min should work in MAINarray and find lowest value in its subarays.

$a[0]=array(0=>522,1=>'Truck');
$a[1]=array(0=>230,1=>'Bear');
$a[2]=array(0=>13,1=>'Feather');
$a[3]=array(0=>40,1=>'Rabit');
$z=min($a);$y=max($a);
echo "The easiest is ".$z[1]." with only ".$z[0]." pounds!<br>";
echo "The heaviest is ".$y[1]." with ".$y[0]." pounds!";

What you say?

Answer 1

Yes, it is reliable. It's safe to assume that min(array(1, 2, ..., n)) is equivalent to min(1, 2, ..., n), and the documentation specifically covers how min compares multiple arrays:

// With multiple arrays, min compares from left to right
// so in our example: 2 == 2, but 4 < 5
$val = min(array(2, 4, 8), array(2, 5, 1)); // array(2, 4, 8)

Answer 2

My understanding of how min works with your type of input is:

1. Only consider the arrays with the fewest number of items.
2. Compare the first elements
3. If there is a tie, compare the next element of each array. Repeat step.

e.g.:

array(
  array(1, "A"),
  array(2),        // min
)


array(
  array(1, "A"),  // min
  array(2, "A"),        
)

array(
  array(1, "Z"),  
  array(1, "A"),  // min
)

I don't have a source for that information, but it's how I remember it working.