note 28118 deleted from control-structures.foreach by sniper

Note Submitter: rlentjes@bigpond.net.au ---- --------- Note 1 --------- Please be aware of what happens with array copy: $arr = array ("one", "two", "three"); next($arr); echo "A: " . current($arr) . "\n"; // two $arr2 = $arr; echo "B: " . current($arr) . "\n"; // one echo "C: " . current($arr2) . "\n"; // two After the copy operation, the copy ($arr2) has the same position as the original ($arr) did before, but the original ($arr) was reset! --------- Note 2 --------- Note that the two arrays do not seem to share the same ELEMENT POINTER as guessed at in some notes above: reset($arr); end($arr2); echo "D: " . current($arr) . "\n"; // one echo "E: " . current($arr2) . "\n"; // three echo "\n"; --------- Note 3 --------- The array copy detail in Note 1 above has an effect on any use of functions like current(). Note that the reference to $arr is the original real variable, note that foreach() modifies the original variable's ELEMENT POINTER. end($arr); echo "A: " . current($arr) . "\n"; // three foreach ($arr as $val1) { echo "\$val1($val1)\n"; echo "B: " . current($arr) . "\n"; // always one foreach ($arr as $val2) { echo "\$val1($val1) \$val2($val2)\n"; echo "C: " . current($arr) . "\n"; // always one } } The $arr internal ELEMENT POINTER was CHANGED from "three" to "one" when the outer foreach() made a copy of $arr for its own use. As a general note, arrays have internal iterators. This is like a GLOBAL VARIABLE being incremented throughout the program (in the same scope as the array, that is). So be aware of this.