Question

I’m wondering if the elements of array can ‘know’ where they are inside of an array and reference that:

Something like…

$foo = array(
   'This is position ' . $this->position,
   'This is position ' . $this->position,
   'This is position ' . $this->position,
),

foreach($foo as $item) {

  echo $item . '\n';
}

//Results:
// This is position 0
// This is position 1
// This is position 2

Answer 1

They can’t “reference themselves” per se, and certainly not via a $this->position as array elements are not necessarily objects. However, you should be tracking their position as a side-effect of iterating through the array:

// Sequential numeric keys:
for ($i = 0; $i < count($array); ++$i) { ... }

// Non-numeric or non-sequential keys:
foreach (array_keys($array) as $key) { ... }
foreach ($array as $key => $value) { ... }

// Slow and memory-intensive way (don't do this)
foreach ($array as $item) {
  $position = array_search($item, $array);
}