python - 如何在python动画中添加图例标签

Question

我正在使用 Matplotlib/Python 绘制数据库中的数据(计数)。我不知道如何拥有一个动画传奇。我希望图例显示该行的当前值。

代码是:

def db_count():
    ### Connect to db and run query ...
    return count

x_data, y_data = [], []
figure = plt.figure()
count = db_count()
line, = plt.plot_date(x_data, y_data, '-', label=count)

def update(frame):
    x_data.append(datetime.now())
    count = db_count()
    y_data.append(count)
    line.set_data(x_data, y_data)
    figure.gca().autoscale_view()
    figure.gca().relim()
    return line,

animation = FuncAnimation(figure, update, interval=60000)

plt.xlabel('Time')
plt.ylabel('Counts')
plt.title('Total counts')
plt.legend(bbox_to_anchor=(1.05, 0.05))
plt.gcf().autofmt_xdate()
plt.xticks(rotation=45)
plt.show()

谢谢

Answer 1

您需要使用 line.set_label(count) 在 update 函数中设置行的标签，然后调用 plt.legend():

def db_count():
    ### Connect to db and run query ...
    return count

x_data, y_data = [], []
figure = plt.figure()
count = db_count()
line, = plt.plot_date(x_data, y_data, '-', label=count)

def update(frame):
    x_data.append(datetime.now())
    count = db_count()
    y_data.append(count)
    line.set_data(x_data, y_data)

    line.set_label(count) # set the label and draw the legend
    plt.legend(bbox_to_anchor=(1.05, 0.05))

    figure.gca().autoscale_view()
    figure.gca().relim()
    return line,

animation = FuncAnimation(figure, update, interval=60000)

plt.xlabel('Time')
plt.ylabel('Counts')
plt.title('Total counts')
plt.gcf().autofmt_xdate()
plt.xticks(rotation=45)
plt.show()