Python for循环报错：int与str类型不支持+=运算的问题排查

错误原因 #

触发TypeError的核心问题是：input().split()返回的是字符串列表。比如你输入170 165 180，student_heights实际是["170", "165", "180"]，每个height都是字符串类型。而total_height初始值是整数0，Python不允许直接把字符串和整数做加法运算，因此报错。

修复后的代码 #

只需要在循环中把height转换成整数类型即可：

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

total_height = 0
for height in student_heights:
  total_height += int(height)  # 将字符串转为整数再累加
print(total_height)

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

代码优化（可选） #

Python内置了更简洁的方法来完成求和与计数，无需手动写循环：

student_heights = input("Input a list of student heights ").split()
# 先把所有输入的字符串转为整数列表
height_list = [int(h) for h in student_heights]

total_height = sum(height_list)
number_of_students = len(height_list)

print(total_height)
print(number_of_students)

内容的提问来源于stack exchange，提问作者Cherie1991