Python - ValueError:关闭文件的I/O操作。

I'm rather new to Python, but based on what I've gathered on the internet it appears that ValueError: I/O operation on closed file is based on not closing the write-to file properly.

对于Python来说，我是新手，但是基于我在internet上收集的内容，它显示了ValueError:关闭文件的I/O操作是基于未正确关闭写入文件的。

I've tried repositioning the close statement to line up with each loop without any success.
I've also attempted to reposition where I originally open the files for writing without any success. I am sure there's an obvious mistake that I'm missing. Your help with identifying this mistake would be greatly appreciated.

我试过重新调整语句的位置，以与每个循环对齐，但没有取得任何成功。我还试图重新定位我最初打开文件的地方，没有任何成功。我肯定我错过了一个明显的错误。非常感谢您帮助我们识别这个错误。

import os       # Loop through files/folders
import xlrd     # Used to read Excel
import time     # Set sleep timers

directory = 'C:/Path/to/file/'

for subdir, dirs, files in   
os.walk(directory):                                                         
# Loop through directory
files = [file for file in files if file.endswith('.xls')]
out_14 = open(str("C:/path/to/file/14.out"), "w")
out_15 = open(str("C:/path/to/file/15.out"), "w")
for file in files:                                                                              # Loop through files in directory
    wb_path = os.path.join(subdir, file)
    wb = xlrd.open_workbook(wb_path)
    ws = wb.sheet_names()
    for worksheet in ws:                                                                        # Loop through worksheets
        sheet = wb.sheet_by_name(worksheet)
        num_rows = sheet.nrows - 1
        num_cells = sheet.ncols - 1
        curr_row = -1
        while curr_row < num_rows:                                                              # Loop through all rows
            temp_14 = []
            temp_15 = []
            curr_row += 1
            curr_cell = -1
            while curr_cell < num_cells:                                                        # Loop through all cells within current row
                curr_cell += 1
                # Cell Types: 0=Empty, 1=Text, 2=Number, 3=Date, 4=Boolean, 5=Error, 6=Blank
                cell_type = sheet.cell_type(curr_row, curr_cell)
                cell_value = sheet.cell_value(curr_row, curr_cell)
                if cell_type == 3:                                                              # Fix Dates yyyy/mm/dd
                    year, month, day, hour, minute, second = xlrd.xldate_as_tuple(cell_value, 0)
                    cell_value = (str(year) + "/" + str(month) + "/" + str(day))
                elif cell_type == 2:                                                            # Round numeric values
                    cell_value = round(cell_value, 3)
                temp_15.append(cell_value)
            out = str('~'.join('"{0}"'.format(item) for item in temp_15))                       # Tilde delimited while encapsulated with quotes
            out_15.write(out)
#                time.sleep(1.0)
    out_15.close()

1 个解决方案

#1

The error is actually raised when trying to write to the file after closing it. It is closed at the end of the first iteration of the loop. On the second iteration, you will get the error.

当尝试在关闭文件后写入文件时，实际上会引发错误。它在循环的第一次迭代结束时关闭。在第二个迭代中，您将得到错误。

You're opening the out_15 file with mode 'w', hence you're going to overwrite it every time you open it. We can then assume you want to open and close it outside your loop for file in files.

打开out_15文件的模式为“w”，因此每次打开它时都会覆盖它。然后，我们可以假定您希望打开并关闭它，以便在文件中进行文件处理。

Then why not use the more modern with statement, and enclose the for loop inside:

那么为什么不使用更现代的语句，并将for循环括在里面:

with open(str("C:/path/to/file/15.out"), "w") as out_15:
    for file in files:
        (...)

That way you don't have to bother closing the file, it will be automatic at the end of the with block. See this question: Valueerror : I/O operation on closed file

这样你就不必费心去关闭文件了，它会自动地在有块的地方结束。查看这个问题:Valueerror: I/O操作的关闭文件。

Other notes: - You're opening out_14 but you never use it and never close it. - Instead of str("C:/...") you can use r"c:......" : r"" is a "raw" string and it will not interpret the backslashes as escape characters. Actually str() isn't necessary in your case.

其他注释:-你打开out_14，但你从不使用它，永远不要关闭它。——而不是str(“C:/…”)可以使用r C:“……”:r是一个“原始”字串，它不会把反斜杠解释为转义字符。实际上，在你的例子中，str()是不必要的。

#1