array(1) {
  [0]=>
  int(5)
}
array(1) {
  [0]=>
  float(5.34)
}
array(1) {
  [0]=>
  string(5) "hello"
}
array(1) {
  [0]=>
  bool(true)
}
array(0) {
}

When converting into arrays, most data types converts into an indexed array with one element.

NULL values converts to an empty array object.