python - 如何在 sklearn 中使用 datasets.fetch_mldata()？

Question

我正在尝试为一个简短的机器学习算法运行以下代码:

import re
import argparse
import csv
from collections import Counter
from sklearn import datasets
import sklearn
from sklearn.datasets import fetch_mldata

dataDict = datasets.fetch_mldata('MNIST Original')

在这段代码中，我试图通过 sklearn 读取 mldata.org 上的数据集“MNIST Original”。这会导致以下错误(有更多行代码，但我在这一行遇到错误):

Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 2.7.3\helpers\pydev\pydevd.py", line 1481, in <module>
    debugger.run(setup['file'], None, None)
  File "C:\Program Files (x86)\JetBrains\PyCharm 2.7.3\helpers\pydev\pydevd.py", line 1124, in run
    pydev_imports.execfile(file, globals, locals) #execute the script
  File "C:/Users/sony/PycharmProjects/Machine_Learning_Homework1/zeroR.py", line 131, in <module>
    dataDict = datasets.fetch_mldata('MNIST Original')
  File "C:\Anaconda\lib\site-packages\sklearn\datasets\mldata.py", line 157, in fetch_mldata
    matlab_dict = io.loadmat(matlab_file, struct_as_record=True)
  File "C:\Anaconda\lib\site-packages\scipy\io\matlab\mio.py", line 176, in loadmat
    matfile_dict = MR.get_variables(variable_names)
  File "C:\Anaconda\lib\site-packages\scipy\io\matlab\mio5.py", line 294, in get_variables
    res = self.read_var_array(hdr, process)
  File "C:\Anaconda\lib\site-packages\scipy\io\matlab\mio5.py", line 257, in read_var_array
    return self._matrix_reader.array_from_header(header, process)
  File "mio5_utils.pyx", line 624, in scipy.io.matlab.mio5_utils.VarReader5.array_from_header (scipy\io\matlab\mio5_utils.c:5717)
  File "mio5_utils.pyx", line 653, in scipy.io.matlab.mio5_utils.VarReader5.array_from_header (scipy\io\matlab\mio5_utils.c:5147)
  File "mio5_utils.pyx", line 721, in scipy.io.matlab.mio5_utils.VarReader5.read_real_complex (scipy\io\matlab\mio5_utils.c:6134)
  File "mio5_utils.pyx", line 424, in scipy.io.matlab.mio5_utils.VarReader5.read_numeric (scipy\io\matlab\mio5_utils.c:3704)
  File "mio5_utils.pyx", line 360, in scipy.io.matlab.mio5_utils.VarReader5.read_element (scipy\io\matlab\mio5_utils.c:3429)
  File "streams.pyx", line 181, in scipy.io.matlab.streams.FileStream.read_string (scipy\io\matlab\streams.c:2711)
IOError: could not read bytes

我曾尝试在互联网上进行研究，但几乎没有任何帮助。非常感谢任何与解决此错误相关的专家帮助。

TIA。

Answer 1

从 0.20 版开始，sklearn deprecates fetch_mldata 函数并添加 fetch_openml相反。

下载MNIST dataset使用以下代码:

from sklearn.datasets import fetch_openml
mnist = fetch_openml('mnist_784')

虽然格式有一些变化。例如，mnist['target'] 是一个字符串类别标签数组(不像以前那样是 float )。