Code: Draw multiple subgraphs

Main return value

ax.flat After searching for a long time, I don’t know what it means, so let’s write it down here

fig, ax = plt.subplots(4, 6)
for i, axi in enumerate(ax.flat):
    axi.imshow(Xtest[i].reshape(62, 47), cmap='bone')
    axi.set(xticks=[], yticks=[])
    axi.set_ylabel(faces.target_names[yfit[i]].split()[-1],
                   color='black' if yfit[i] == ytest[i] else 'red')
fig.suptitle('Predicted Names; Incorrect Labels in Red', size=14);
plt.show()

Finally, to draw a picture, you must plt.show, imshow only processes the matrix and does not make a picture

2. Confusion matrix heat map drawing:

from sklearn.metrics import confusion_matrix
import seaborn as sns; 
mat = confusion_matrix(ytest, yfit)
sns.heatmap(mat.T, square=True, annot=True, fmt='d', cbar=False,
            xticklabels=faces.target_names,
            yticklabels=faces.target_names)
plt.ylabel('predicted label');

effect: