唯一的问题是它会抛出“IndentationError:”当我使用 try except 和“with open('file_name', 'mode') as file_handler:”时

Question

据我所知，我已经完成了正确的缩进，我还在另一个文本编辑器中尝试了相同的代码，但它引发了相同的错误。

当我使用 try except 和“with open('file_name', 'mode') as file_handler:”时，它会抛出“IndentationError:”

python3 test2.py 文件“test2.py”，第 9 行 除了 IO 错误： ^ IndentationError：预期有一个缩进块

我学过类似的文章，它有意识地表示缩进。我也尝试过使用制表符和 4 个空格，但无论如何都不起作用。 也许这是一个我没有意识到的愚蠢错误。 请帮助我，我将很感激获得在这段代码中做得更好的建议，以便我可以学到一些东西。

f_name = input("enter a file name:: ")

if f_name == 'na na boo boo':
    print(f"\n{f_name} TO YOU - You have been punk'd!\n")
    exit()
try:
    with open(f_name, 'r') as f_hand:

except IOError:
    print(f'File missing:: {f_name}.')
    exit()

    floating_points = []

    for line in f_hand:

        if line.startswith('X-DSPAM') :
            start_index_pos = line.find(':')
            start_index_pos = float(start_index_pos)
            floating_points.append(start_index_pos)
    print("The floating points are::\n")

    for floating_point in floating_points:
        print(floating_point)
    print(f"There are {len(floating_points)} items on the list and they sum to {sum(floating_points)}.")

Answer 1

您不能使用 try 语句的 except 子句中断 with 语句。它必须首先完成。某些代码可以移出 with 语句，并放置在 try 语句之前或之后（视情况而定）

floating_points = []

try:
    with open(f_name, 'r') as f_hand:
        for line in f_hand:
            if line.startswith('X-DSPAM') :
                start_index_pos = line.find(':')
                start_index_pos = float(start_index_pos)
                floating_points.append(start_index_pos)
except FileNotFoundError:
    print(f'File missing:: {f_name}.')
    exit()

print("The floating points are::\n")
for floating_point in floating_points:
    print(floating_point)
print(f"There are {len(floating_points)} items on the list and they sum to {sum(floating_points)}.")

Answer 2

您的代码完全错误，您不只是使用上下文管理器来打开文件，为此，我们有 open()，我们使用 with 作为上下文管理器，以便它能够处理稍后自动关闭文件。

并且语法是错误的，你不能只让 with 语句挂上 :，对文件的操作必须在 with 缩进内。

无论如何，这是正确的代码

f_name = input("enter a file name:: ")

if f_name == 'na na boo boo':
    print(f"\n{f_name} TO YOU - You have been punk'd!\n")
    exit()
try:
    with open(f_name, 'r') as f_hand:
        floating_points = []

        for line in f_hand:

            if line.startswith('X-DSPAM'):
                start_index_pos = line.find(':')
                start_index_pos = float(start_index_pos)
                floating_points.append(start_index_pos)
        print("The floating points are::\n")

        for floating_point in floating_points:
            print(floating_point)
        print(f"There are {len(floating_points)} items on the list and they sum to {sum(floating_points)}.")
except IOError:
    print(f'File missing:: {f_name}.')
    exit()