Why does PHP overwrite values when I iterate through this array twice (by reference, by value)

Question

If I iterate through an array twice, once by reference and then by value, PHP will overwrite the last value in the array if I use the same variable name for each loop. This

Answer 1

Here's an explanation from the man himself:

$y = "some test";

foreach ($myarray as $y) {
    print "$y\n";
}

Here $y is a symbol table entry referencing a string containing "some test". On the first iteration you essentially do:

$y = $myarray[0];  // Not necessarily 0, just the 1st element

So now the storage associated with $y is overwritten by the value from $myarray. If $y is associated with some other storage through a reference, that storage will be changed.

Now let's say you do this:

$myarray = array("Test");
$a = "A string";
$y = &$a;

foreach ($myarray as $y) {
    print "$y\n";
}

Here $y is associated with the same storage as $a through a reference so when the first iteration does:

$y = $myarray[0];

The only place that "Test" string can go is into the storage associated with $y.