array(3) {
  [0]=>
  int(1)
  [1]=>
  string(5) "hello"
  [2]=>
  float(3.5)
}
array(4) {
  [0]=>
  int(1)
  [1]=>
  string(5) "hello"
  [2]=>
  float(3.5)
  [4]=>
  string(5) "world"
}