错误是因为只能将列表（而不是“NoneType”）连接到列表中

Question

I want to reverse the Jamies_list and Drews list should be in first then attach both the list and I want to return the complete list.

def combine_lists(list1, list2):
  # Generate a new list containing the elements of list2
  # Followed by the elements of list1 in reverse order
  return(list2+list1.reverse())
    
Jamies_list = ["Alice", "Cindy", "Bobby", "Jan", "Peter"]
Drews_list = ["Mike", "Carol", "Greg", "Marcia"]

print(combine_lists(Jamies_list, Drews_list))

Answer 1

.reverse() is an inplace operation. It won't return the reversed list, it returns None

Use sorted(list1, reverse=True) .

def combine_lists(list1, list2):
  # Generate a new list containing the elements of list2
  # Followed by the elements of list1 in reverse order
  return(list2+sorted(list1, reverse=True))
    
Jamies_list = ["Alice", "Cindy", "Bobby", "Jan", "Peter"]
Drews_list = ["Mike", "Carol", "Greg", "Marcia"]

print(combine_lists(Jamies_list, Drews_list))

ELSE

def combine_lists(list1, list2):
  # Generate a new list containing the elements of list2
  # Followed by the elements of list1 in reverse order
  list1.reverse()
  return(list2+list1)
    
Jamies_list = ["Alice", "Cindy", "Bobby", "Jan", "Peter"]
Drews_list = ["Mike", "Carol", "Greg", "Marcia"]

print(combine_lists(Jamies_list, Drews_list))

ELSE

def combine_lists(list1, list2):
  # Generate a new list containing the elements of list2
  # Followed by the elements of list1 in reverse order
  return list2 + list1[::-1]
    
Jamies_list = ["Alice", "Cindy", "Bobby", "Jan", "Peter"]
Drews_list = ["Mike", "Carol", "Greg", "Marcia"]

print(combine_lists(Jamies_list, Drews_list))

Answer 2

reverse() is an inbuilt method in Python programming language that reverses objects of the list in place

You can also check it by using print(list1.reverse()). It will print None.

So would suggest using return list2 + list1[::-1]