我怎样才能很好地可视化混淆矩阵？

Question

I'm working on a classification problem and I wanted to visualize confusion matrix. But i have a problem is that the number are not in the middle. Here you can see the code:

lr = LogisticRegression()
lr.fit(X_train,Y_train)
y_test_pred = lr.predict(X_test)
print("The accuracy of the logistic regression : ",(accuracy_score(y_test_pred,Y_test)*100), "%")

confusion_matrix = pd.crosstab(Y_test, y_test_pred, rownames=['Actual'], colnames=['Predicted'])
cm = confusion_matrix.astype('float') / confusion_matrix.sum(axis=1)[:, np.newaxis]

# Visualization
plt.figure 
plt.title('Logistic Regression')
sns.heatmap(cm, annot=True)
plt.show()

The output is something like that: screen

How can I solve this problem?

Answer 1

from sklearn.metrics import confusion_matrix
import matplotlib.pyplot as plt
cm=confusion_matrix(y,y_pred)
plt.matshow(cm,cmap=plt.cm.Greens)
plt.colorbar() 
plt.show()

plt.matshow() can help.

Add how to put the number in the middle. Key words: horizontalalignment, verticalalignment can locate the position of annotation.

    import matplotlib.pyplot as plt
    plt.matshow(cm,cmap=plt.cm.Greens)  # plot matrix    
    plt.colorbar() 

    for i in range(len(cm)):
        for j in range(len(cm)):
            plt.annotate(cm[i,j],xy=(j,i),horizontalalignment='center',verticalalignment='center',size=15,color='orange') 

Answer 2

I ran into the same problem. In my case, I only uninstall the existing version of matplotlib and reinstall it with version 3.0.0. It works for me, (I know it's not a permanent solution. though).

First:

pip uninstall matplotlib

And then:

pip install matplotlib==3.0

Hope it helps.