KeyError: 46220

Question

edited to address the comments

added lines at the beginning where the data was imported from MNIST
added the full error message from jupyter notebook as text

I am trying to implement a very simple code in python (jupyter notebook, if it matters):

    from sklearn.datasets import fetch_openml
    x, y = fetch_openml('mnist_784', version=1, return_X_y=True, data_home='./data/')
    y = y.astype(int)

fig, ax = plt.subplots(2, 4, figsize=(20, 8))
for a in ax.ravel():
    j = np.random.choice(len(y))
    sns.heatmap(x[j].reshape(28,28), ax=a, cbar=False, cmap='gray_r')
    a.set_title(f'Label: {y[j]}')
    a.set_xticks([])
    a.set_yticks([])

and I get the following error shown in the screenshot. I don't think this is a code problem, as this was taken directly from the lecturer's notes. Could anyone help me troubleshoot and enlighten me, please?

See error message below:

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3079             try:
-> 3080                 return self._engine.get_loc(casted_key)
   3081             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: 46220

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

KeyError                                  Traceback (most recent call last)
 in 
      2 for a in ax.ravel():
      3     j = np.random.choice(len(y))
----> 4     sns.heatmap(x[j].reshape(28,28), ax=a, cbar=False, cmap='gray_r')
      5     a.set_title(f'Label: {y[j]}')
      6     a.set_xticks([])

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/frame.py in __getitem__(self, key)
   3022             if self.columns.nlevels > 1:
   3023                 return self._getitem_multilevel(key)
-> 3024             indexer = self.columns.get_loc(key)
   3025             if is_integer(indexer):
   3026                 indexer = [indexer]

~/opt/anaconda3/lib/python3.8/site-packages/pandas/core/indexes/base.py in get_loc(self, key, method, tolerance)
   3080                 return self._engine.get_loc(casted_key)
   3081             except KeyError as err:
-> 3082                 raise KeyError(key) from err
   3083 
   3084         if tolerance is not None:

KeyError: 46220

KeyError: 46220

user_14774959 · Answer

I suppose that with the line below you were trying to access the row j of the pandas DataFrame x:

sns.heatmap(x[j].reshape(28,28), ax=a, cbar=False, cmap='gray_r')

However in order to access the values of a row by name you should use x.iloc[j].values instead. Lots of examples can be found here.

The complete code is:

from sklearn.datasets import fetch_openml
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

x, y = fetch_openml('mnist_784', version=1, return_X_y=True, data_home='./data/')
y = y.astype(int)

fig, ax = plt.subplots(2, 4, figsize=(20, 8))
for a in ax.ravel():
    j = np.random.choice(len(y))
    sns.heatmap(x.iloc[j].values.reshape(28,28), ax=a, cbar=False, cmap='gray_r')
    a.set_title(f'Label: {y[j]}')
    a.set_xticks([])
    a.set_yticks([])

The result produced:

KeyError: 46220

1 Answers