使用 ZipFile 中的 ImageIO 处理文件

Question

我在尝试使用 imageio 从 zip 文件读取图像文件时遇到错误：

import zipfile
import glob
import imageio
from os.path import splitext

    for database in glob.iglob('Datasets/*.zip'):
        print(database)
        zf = zipfile.ZipFile(database, 'r')
        for file in zf.namelist():
            basename,extension = splitext(file)
            if extension == '.png':
                img = imageio.imread(file)
                print(img.shape, end='')

这是回溯：

Datasets/first.zip
Traceback (most recent call last):
  File "testZip.py", line 12, in <module>
    img = imageio.imread(file)
  File "/usr/local/anaconda3/lib/python3.6/site-packages/imageio/core/functions.py", line 200, in imread
    reader = read(uri, format, 'i', **kwargs)
  File "/usr/local/anaconda3/lib/python3.6/site-packages/imageio/core/functions.py", line 117, in get_reader
    request = Request(uri, 'r' + mode, **kwargs)
  File "/usr/local/anaconda3/lib/python3.6/site-packages/imageio/core/request.py", line 120, in __init__
    self._parse_uri(uri)
  File "/usr/local/anaconda3/lib/python3.6/site-packages/imageio/core/request.py", line 252, in _parse_uri
    raise IOError("No such file: '%s'" % fn)
OSError: No such file: 'first/image_7395.png'
[Finished in 0.2s with exit code 1]

Answer 1

file 变量包含一个文件名，而不是实际的文件数据。错误非常明显：磁盘上不存在名为 first/image_7395.png 的文件 - 虽然它在 zip 中。您需要从 zip 中提取文件并将提取的文件用于 imageio。例如：

for database in glob.iglob('Datasets/*.zip'):
    print(database)
    zf = zipfile.ZipFile(database, 'r')
    for file in zf.namelist():
        basename,extension = splitext(file)
        if extension == '.png':
            ofile = zf.extract(file)
            img = imageio.imread(ofile)
            print(img.shape, end='')
            # if you need to:
            os.remove(ofile)

编辑：看起来 imageio 也可以从类似文件的对象中读取，在这种情况下，您可以使用 ZipFile.open() 并将其传递给 imageio。例如：

# ...
if extension == '.png':
    with zf.open(file) as img_file:
        img = imageio.read(img_file)

Answer 2

您正在尝试按名称打开 ZIP 中的图像。 imageio 不知道该怎么做。它假定您给了它一个真实的文件路径。您需要首先打开 zip 中的文件，为其提供一个文件对象。您也可以像@randomdude999 建议的那样先提取它。

for file in zf.namelist():
    basename,extension = splitext(file)
    if extension == '.png':
        img = imageio.imread(zf.open(file))
        print(img.shape, end='')

使用 ZipFile 中的 ImageIO 处理文件

Processing files with ImageIO from a ZipFile

python

python-zipfile