$field_array1 = array(
			'a' => 1,
			'b' => 1,
			'c' => 1,
			'd' => 1,
		);		

foreach(array_keys($field_array1) as $key){
    echo $key."\n";
}





$array = array('first'=>'111', 'second'=>'222', 'third'=>'333');

  // get the first key: returns 'first'
  print array_shift(array_keys($array));

  // get the last key: returns 'third'
  print array_pop(array_keys($array));

  // get the first value: returns '111'
  print array_shift(array_values($array));

  // get the last value: returns '333'
  print array_pop(array_values($array));