Question

我正在尝试用Python解压缩gzip文件。 gzip文件从Internet下载，然后在本地保存，然后尝试解压缩。由于某种原因，输出文件返回0bytes。当我通过应用程序手动提取文件时，数据是一个.list文件，在重命名时可以正常工作.txt文件。有人能让我知道为什么输出解压缩文件中没有数据？还在学习Python。

def downloadExtractMovies():
    moviePath = os.path.join(currentDir,moviesList)
    response_movies = open(moviePath, 'w')
    f = urlopen(reqMovies)
    local_file = open(moviesList, "w")
    local_file.write(f.read())
    response_movies.close()
    decompressedFile = gzip.GzipFile(fileobj=local_file, mode='rb')

    with open(outFilePath_movies, 'w') as outfile:
        outfile.write(decompressedFile.read())

    local_file.close()

由于

编辑：我通过将文件对象包装到StringIO中来解决问题。但是，当我提取一个输出160MB文件的文件时，它运行得很好。但是当我运行一个更大的文件，比如220MB时，它给了我一个记忆错误。

以下是代码：

def downloadExtractMovies():
    moviePath = os.path.join(currentDir,moviesList)

    response_movies = open(moviePath, 'w')
    f = urlopen(reqMovies)
    url_f = StringIO.StringIO(f.read())

    with open(moviesList, 'wb') as local_file:
        local_file.write(f.read())

    response_movies.close()

    decompressedFile = gzip.GzipFile(fileobj=url_f, mode='rb')

    with open(outFilePath_movies, 'w') as outfile:
        outfile.write(decompressedFile.read())

这是追溯：

  File "D:\Portable Python 2.7.6.1\App\lib\gzip.py", line 254, in read
    self._read(readsize)
  File "D:\Portable Python 2.7.6.1\App\lib\gzip.py", line 313, in _read
    self._add_read_data( uncompress )
  File "D:\Portable Python 2.7.6.1\App\lib\gzip.py", line 331, in     _add_read_data
self.extrabuf = self.extrabuf[offset:] + data
MemoryError

Answer 1

该文件与close一起编写。因此，您必须先关闭该文件，然后再重新打开它。最好使用with - 语句，它会自动关闭文件：

with open(moviesList, "wb") as local_file:
    local_file.write(f.read())

而不是自己阅读和写作，使用shutil.copyfileobj，这是更有效的内存。如果您不需要磁盘上的压缩数据，则可以直接使用urllib-object：

def downloadExtractMovies(reqMovies, outFilePath_movies):
    decompressedFile = gzip.GzipFile(fileobj=urlopen(reqMovies), mode='rb')
    with open(outFilePath_movies, 'w') as outfile:
        shutil.copyfileobj(decompressedFile, outfile)

Python中的Gzip解压缩：文件输出为空

1 个答案: