python csv库对关闭文件的I/O操作

Question

在 csv_reader 中循环每一行时，我遇到了“关闭文件的 I/O 操作”问题。

这是我的代码：

logFile = request.FILES['logs']
array = []
with logFile as csv_file:
    field_names = ['hi', 'hi', 'hello', 'hello' ]
    delimiter = ','
    quote_character = '"'
    csv_reader = csv.DictReader(csv_file, fieldnames=field_names , delimiter = delimiter, quotechar = quote_character)
    count = 0
    for rows in csv_reader:
        if count == 0:
            print count
        else:
            print count
            array.append(rows)
        count += 1

return array

logFile 是用户上传的实际 csv 文件，而不是路径。

Traceback:
File "/app/.heroku/python/lib/python2.7/site-packages/django/core/handlers/base.py" in     get_response
  111. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/home/vcap/app/BillingWebApp/views.py" in IndexView
  128. csv_list_dict = csv_getting_list_dict.Csv_Parser(logFile)
File "/home/vcap/app/BillingWebApp/csv_getting_list_dict.py" in Csv_Parser
  5. with logFile.open() as csv_file:
File "/app/.heroku/python/lib/python2.7/site-packages/django/core/files/uploadedfile.py" in open
  97. self.file.seek(0)

Exception Type: ValueError at /
Exception Value: I/O operation on closed file.

错误发生在我的代码中：

    for rows in csv_reader:

在调试器中它得到了这个：

row = self.reader.next()

Answer 1

LogFile的类型是：

<class 'django.core.files.uploadedfile.InMemoryUploadedFile'>

对于with logFile as csv_file: 语句，您需要文件对象，即<type 'file'>。

您需要将LogFile保存到文件中，然后再次打开文件以进行下一个过程。

Answer 2

首先读取文件。您可能想尝试类似的方法：

data = [row for row in csv.DictReader(csv_file.read(), fieldnames=field_names,
           delimiter=delimiter, quotechar=quote_character)]

Answer 3

这种方法假设您的 csv 文件可以加载到内存中：

from cStringIO import StringIO

log_file = request.FILES['logs']
log_file.seek(0)
log_file_content = log_file.read()
in_memory_log_file = StringIO(log_file_content)

array = []

field_names = ['hi', 'hi', 'hello', 'hello' ]
delimiter = ','
quote_character = '"'
csv_reader = csv.DictReader(in_memory_log_file, fieldnames=field_names , 
                            delimiter = delimiter, quotechar = quote_character)
count = 0
for row in csv_reader:
    if count == 0:
        print count
    else:
        print count
        array.append(row)
    count += 1

return array