如何获取CSV读取器读取内存文件？

问题描述

我试图获取一个完整的文件到内存（完成 - 使用StringIO） - 但这些对象的行为真的不像真正的文件，只要我看到 - 我得到的全部内容，或我可以一次读取一行，但我无法解决如何应用此模式：

I'm trying to fetch an entire file into memory (done - using StringIO) - but these objects don't really behave exactly like 'real' files as far as I can see - I get the whole contents, or I can read a line at a time, but I can't work out how to apply this pattern:

import csv
with open(#MYMEMORYFILE_HERE#, 'rb') as csvfile:
        spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
        for row in spamreader:

有一种方法来处理一个内存文件就像一个磁盘文件，所以我可以使用更好的习惯？

Is there a way of treating a memoryfile just like an on-disk file , so I can use the nicer idioms above ?

Python 2.7.4 (default, Apr 19 2013, 18:28:01)

编辑：感谢您的答案 - 我想我已经缩小了什么让我困惑...但我还有一个问题，以下不输出什么？我怀疑刷新？

Thanks for the answers on this - I think I have narrowed down what was confusing me...but I still have an issue here, the following doesn't output anything? I suspect flushing ?

from csv import reader, writer
import StringIO

memfile=StringIO.StringIO()
spamwriter = writer(memfile)
spamwriter.writerow(['Spam'] * 5 + ['Baked Beans'])
spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])
spamreader=reader(memfile)
for row in spamreader:
        print ', '.join(row)
memfile.close()

编辑＃2：但我正在咆哮错误的树我想： （'IOError：File not open for reading' - 当我调用已经打开的文件上的读取时...）
编辑＃3：放弃StringIO没有真正需要它） - 根据答案使用分割线。

EDIT#2: But I'm barking up the wrong tree I think: I couldn't get the on-disk version of this to work either ('IOError: File not open for reading' - when I call the read on the already open file...)EDIT#3: abandoned the StringIO (no real need for it) - used splitlines as per the answer.

我会在这里留下代码和注释 - 万一有用。 （即使它是一个死胡同）。

I'll leave the code and comments here - in case it's useful. (even though it is a cul-de-sac).

推荐答案

如果你想读取整个文件到内存，它的文本，你不需要打开一个StringIO对象。只需读取它作为一个字符串！

If you want to read a whole file into memory, and it's text, you don't need to open a StringIO object. Just read it as a string!

with open(filename, 'r') as file:
    in_memory_file = file.read()

然后您可以使用 splitlines 以迭代方式迭代打开的文本文件。

Then you can use splitlines to iterate over it the way you would iterate over an open text file.

spamreader = csv.reader(in_memory_file.splitlines(), delimiter=' ', quotechar='|')
for row in spamreader:
    pass

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