问题是total_height变量是一个数字，而height变量是一个字符串，因为input()函数返回的是一个字符串，为了将这两个变量相加，必须先用int(height)将height转换为整数，如下所示：

student_heights = input("Input a list of studen heights ").split()

total_height = 0
for height in student_heights:
  total_height += int(height)
print(total_height)

number_of_students = 0
for student in student_heights:
  number_of_students += 1
print(number_of_students)

或者，你可以把student_heights列表从map()开始转换成一个数字列表，这可能会让你的代码更直观一些，比如：

student_heights = map(int, input("Input a list of studen heights ").split())

total_height = 0
for height in student_heights:
  total_height += height
print(total_height)

number_of_students = 0
for student in student_heights:
  number_of_students += 1
print(number_of_students)