import matplotlib.pyplot as plt

import itertools

def plot_confusion_matrix(cm, classes,

                          title='Confusion matrix',

                          cmap=plt.cm.Blues):

    """

    This function prints and plots the confusion matrix.
　　 cm:混淆矩阵值
　　 classes:分类标签
　　 """

    plt.imshow(cm, interpolation='nearest', cmap=cmap)

    plt.title(title)

    plt.colorbar()

    tick_marks = np.arange(len(classes))

    plt.xticks(tick_marks, classes, rotation=0)

    plt.yticks(tick_marks, classes)

    thresh = cm.max() / 2.

    for i, j in itertools.product(range(cm.shape[0]), range(cm.shape[1])):

        plt.text(j, i, cm[i, j],

                 horizontalalignment="center",

                 color="white" if cm[i, j] > thresh else "black")

    plt.tight_layout()

    plt.ylabel('True label')

    plt.xlabel('Predicted label')