如果文件不存在则重新运行代码不起作用

Question

我有这段代码来读取文件

def collect_exp_data(file_name):
    data = dict()
    while True:
        try:
           with open(file_name, 'r') as h:
                break
                for line in h:
                batch, x, y, value = line.split(',')                            
                try: 
                    if not batch in data:
                        data[batch] = []
                    data[batch] += [(float(x), float(y), float(value))]
                except ValueError: 
                    print("\nCheck that all your values are integers!")   
        except FileNotFoundError:
            print("\nThis file doesn't exist, Try again!")
    return data

我正在尝试添加一些错误处理，我想重新要求用户输入文件以防文件不存在，但代码只是返回一个无限循环？ 我做错了什么，我该如何解决？

编辑：

如果我尝试将 while 循环带到外面，那么它会在文件不存在的情况下工作，但如果文件存在，代码只是在循环后停止而不是接下来运行 function，这是代码

def collect_exp_data(file_name):
    data = dict()
    with open(file_name, 'r') as h:
        for line in h:
            batch, x, y, value = line.split(',')                           
        try: 
            if not batch in data:
                data[batch] = []
            data[batch] += [(float(x), float(y), float(value))]
        except ValueError: 
            print("\nCheck that all your values are integers!")   
    return data

while True:
    file_name = input("Choose a file: ")
    try:
        data = collect_exp_data(file_name)
        break
    except FileNotFoundError:
        print('This file does not exist, try again!')

Answer 1

制造一个打破循环的条件

finished = False
while not finished:
    file_name = input("Choose a file: ")
    try:
        data = collect_exp_data(file_name)
        # we executed the previous line succesfully,
        # so we set finished to true to break the loop
        finished = True
    except FileNotFoundError:
        print('This file does not exist, try again!')
        # an exception has occurred, finished will remain false
        # and the loop will iterate again

Answer 2

在主 function 中执行所有异常处理。

def collect_exp_data(filename):
    data = dict()
    with open(filename) as infile:
        for line in map(str.strip, infile):
            batch, *v = line.split(',')
            assert batch and len(v) == 3
            data.setdefault(batch, []).extend(map(float, v))
    return data

while True:
    filename = input('Choose file: ')
    try:
        print(collect_exp_data(filename))
        break
    except FileNotFoundError:
        print('File not found')
    except (ValueError, AssertionError):
        print('Unhandled file content')

显然，如果禁用调试，断言将不起作用，但你明白了