machine-learning - 为什么在 MNIST 分类器代码中使用 X[0] 会给我一个错误？

Question

我正在学习使用 MNIST 数据集进行分类。我遇到了一个错误，我无法弄清楚，我已经做了很多谷歌搜索，但我什么也做不了，也许你是专家，可以帮助我。这是代码 -

>>> from sklearn.datasets import fetch_openml
>>> mnist = fetch_openml('mnist_784', version=1)
>>> mnist.keys()

输出：dict_keys(['data', 'target', 'frame', 'categories', 'feature_names', 'target_names', 'DESCR', 'details', 'url'])

>>> X, y = mnist["data"], mnist["target"]
>>> X.shape

输出：(70000, 784)

>>> y.shape

输出：（70000）

>>> X[0]

output:KeyError                                  Traceback (most recent call last)
c:\users\khush\appdata\local\programs\python\python39\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2897             try:
-> 2898                 return self._engine.get_loc(casted_key)
   2899             except KeyError as err:

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

pandas\_libs\hashtable_class_helper.pxi in pandas._libs.hashtable.PyObjectHashTable.get_item()

KeyError: 0

The above exception was the direct cause of the following exception:

KeyError                                  Traceback (most recent call last)
<ipython-input-10-19c40ecbd036> in <module>
----> 1 X[0]

c:\users\khush\appdata\local\programs\python\python39\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)
   2904             if self.columns.nlevels > 1:
   2905                 return self._getitem_multilevel(key)
-> 2906             indexer = self.columns.get_loc(key)
   2907             if is_integer(indexer):
   2908                 indexer = [indexer]

c:\users\khush\appdata\local\programs\python\python39\lib\site-packages\pandas\core\indexes\base.py in get_loc(self, key, method, tolerance)
   2898                 return self._engine.get_loc(casted_key)
   2899             except KeyError as err:
-> 2900                 raise KeyError(key) from err
   2901 
   2902         if tolerance is not None:

KeyError: 0

请回答，可能会有一个愚蠢的错误，因为我是 ML 的初学者。如果您也给我一些提示，那将非常有帮助。

标签： machine-learningmnist

Answer 1

我也面临同样的问题。

• scikit 学习：0.24.0
• matplotlib：3.3.3
• 蟒蛇：3.9.1

我曾经使用下面的代码来解决问题。

import matplotlib as mpl
import matplotlib.pyplot as plt


# instead of some_digit = X[0]
some_digit = X.to_numpy()[0]
some_digit_image = some_digit.reshape(28,28)

plt.imshow(some_digit_image,cmap="binary")
plt.axis("off")
plt.show()