Popping elements off end of an unreferenced array ---( Array with 1 element(s): )--- --> State of array before loop: array(1) { [0]=> string(3) "v.0" } --> Do loop: iteration 0: $k=0; $v=v.0 --> State of array after loop: array(0) { } ---( Array with 2 element(s): )--- --> State of array before loop: array(2) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 --> State of array after loop: array(0) { } ---( Array with 3 element(s): )--- --> State of array before loop: array(3) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 --> State of array after loop: array(0) { } ---( Array with 4 element(s): )--- --> State of array before loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 iteration 3: $k=3; $v=v.3 --> State of array after loop: array(0) { } Shift elements off start of an unreferenced array ---( Array with 1 element(s): )--- --> State of array before loop: array(1) { [0]=> string(3) "v.0" } --> Do loop: iteration 0: $k=0; $v=v.0 --> State of array after loop: array(0) { } ---( Array with 2 element(s): )--- --> State of array before loop: array(2) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 --> State of array after loop: array(0) { } ---( Array with 3 element(s): )--- --> State of array before loop: array(3) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 --> State of array after loop: array(0) { } ---( Array with 4 element(s): )--- --> State of array before loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 iteration 3: $k=3; $v=v.3 --> State of array after loop: array(0) { } Remove current element of an unreferenced array ---( Array with 1 element(s): )--- --> State of array before loop: array(1) { [0]=> string(3) "v.0" } --> Do loop: iteration 0: $k=0; $v=v.0 --> State of array after loop: array(0) { } ---( Array with 2 element(s): )--- --> State of array before loop: array(2) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 --> State of array after loop: array(0) { } ---( Array with 3 element(s): )--- --> State of array before loop: array(3) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 --> State of array after loop: array(0) { } ---( Array with 4 element(s): )--- --> State of array before loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 iteration 3: $k=3; $v=v.3 --> State of array after loop: array(0) { } Adding elements to the end of an unreferenced array ---( Array with 1 element(s): )--- --> State of array before loop: array(1) { [0]=> string(3) "v.0" } --> Do loop: iteration 0: $k=0; $v=v.0 --> State of array after loop: array(2) { [0]=> string(3) "v.0" [1]=> string(5) "new.0" } ---( Array with 2 element(s): )--- --> State of array before loop: array(2) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 --> State of array after loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(5) "new.0" [3]=> string(5) "new.1" } ---( Array with 3 element(s): )--- --> State of array before loop: array(3) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 --> State of array after loop: array(6) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(5) "new.0" [4]=> string(5) "new.1" [5]=> string(5) "new.2" } ---( Array with 4 element(s): )--- --> State of array before loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 iteration 3: $k=3; $v=v.3 --> State of array after loop: array(8) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" [4]=> string(5) "new.0" [5]=> string(5) "new.1" [6]=> string(5) "new.2" [7]=> string(5) "new.3" } Adding elements to the start of an unreferenced array ---( Array with 1 element(s): )--- --> State of array before loop: array(1) { [0]=> string(3) "v.0" } --> Do loop: iteration 0: $k=0; $v=v.0 --> State of array after loop: array(2) { [0]=> string(5) "new.0" [1]=> string(3) "v.0" } ---( Array with 2 element(s): )--- --> State of array before loop: array(2) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 --> State of array after loop: array(4) { [0]=> string(5) "new.1" [1]=> string(5) "new.0" [2]=> string(3) "v.0" [3]=> string(3) "v.1" } ---( Array with 3 element(s): )--- --> State of array before loop: array(3) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 --> State of array after loop: array(6) { [0]=> string(5) "new.2" [1]=> string(5) "new.1" [2]=> string(5) "new.0" [3]=> string(3) "v.0" [4]=> string(3) "v.1" [5]=> string(3) "v.2" } ---( Array with 4 element(s): )--- --> State of array before loop: array(4) { [0]=> string(3) "v.0" [1]=> string(3) "v.1" [2]=> string(3) "v.2" [3]=> string(3) "v.3" } --> Do loop: iteration 0: $k=0; $v=v.0 iteration 1: $k=1; $v=v.1 iteration 2: $k=2; $v=v.2 iteration 3: $k=3; $v=v.3 --> State of array after loop: array(8) { [0]=> string(5) "new.3" [1]=> string(5) "new.2" [2]=> string(5) "new.1" [3]=> string(5) "new.0" [4]=> string(3) "v.0" [5]=> string(3) "v.1" [6]=> string(3) "v.2" [7]=> string(3) "v.3" }