python - 错误陷阱与计数器结合使用不起作用

Question

我正在编写使用户逐行输入RLE的代码。然后，我将输入的数据发送到对它进行解码的函数。在函数中，我包含了一些基本的错误陷阱。

我的错误是，当用户只能输入不正确的数据时，他们选择的次数(他们选择他们要输入的行数)。也就是说，如果用户输入了RLE的2条(共3条)正确的行，然后输入了不正确的行，则代码不会要求再次输入RLE，但是如果用户在第一个或第二个输入中输入了不正确的行，它将起作用。

码:

if line_amount>2:
            print ("Please enter the compressed data one line at a time")
            while line_amount > counter:
                compressed_data = input('->') #ENTER RLE DATA
                counter+=1
                RLEtoASCII(compressed_data,counter)

RLEtoASCII:

def RLEtoASCII(compressed_data,counter):
    try:
        pairs = [(int(compressed_data[i:i+2]), compressed_data[i+2]) for i in range(0, len(compressed_data), 3)]
        global text
        text = ''.join(n * c for n, c in pairs)
        RLE_Inputs = open("Entered Data.txt", 'a+') #File that lists all the inputs
        #[etc all the file writing]
    except:
        print('THERE WAS A PROBLEM WITH THE VALUES Please re-enter values.\n')

如果我尝试在除外之后调用RLEtoASCII，则会创建一个循环。除外后counter -=1似乎不起作用...

Answer 1

通过将错误处理移出函数并移至if循环，我们可以更轻松地控制迭代:

if line_amount>2:
            print ("Please enter the compressed data one line at a time")
            while line_amount > counter:
                compressed_data = input('->') #ENTER RLE DATA
                if compressed_data != '':
                    try:
                        RLEtoASCII(compressed_data)
                        counter+=1
                    except:
                        print('THERE WAS A PROBLEM WITH THE VALUES Please re-enter values.\n')

RLEtoASCII:

def RLEtoASCII(compressed_data):
    pairs = [(int(compressed_data[i:i+2]), compressed_data[i+2]) for i in range(0, len(compressed_data), 3)]
    global text
    text = ''.join(n * c for n, c in pairs)
    RLE_Inputs = open("Entered Data.txt", 'a+') #File that lists all the inputs
    #[etc all the file writing]