为什么我会得到“不受支持的操作数类型错误？

Question

我在编码时遇到了这个错误，我不知道它的含义。

line 59, in <module> 
    filename=class_name + ".csv" 
TypeError: unsupported operand type(s) for +: 'int' and 'str' 

我不知道我在哪弄乱了，但它可能是与类号验证。

while True: 
    try: 
     class_name=int(input("Are you in class 1, 2 or 3? ")) 
     if class_name in [1, 2, 3]: 
      print(name,", welcome to this maths test!") 
      break 
     else: 
      print ("Class has to be 1, 2 or 3") 
    except ValueError: 
     print ("Class has to be 1, 2 or 3") 



filename=class_name + ".csv" 

with open(filename, 'a') as f: 
     f.write(str(name) + " : " + str(score) + '\n') 

if results("Do you wish to view previous results for your class? (yes or no) "): 
     with open(filename, 'r') as f: 
      print(f.read()) 

Answer 1

class_name是int。在这里，您给它分配：

class_name=int(input("Are you in class 1, 2 or 3? ")) 

但是，你不能连接整数和字符串，让你有int先转换为str：

filename= str(class_name) + ".csv"