Dynamic plotting class with multiline support

Dynamic plotting

%matplotlib notebook

import numpy as np
import matplotlib.pyplot as plt
from matplotlib import colors as mcolors

class DynamicPlot():

    colors = list(mcolors.cnames.values())
    
    def __init__(self, data):
        self.figure, self.ax = plt.subplots(figsize=(12, 10))
        self.lines = {}
        for i, key in enumerate(data):
            self.lines[key], = self.ax.plot([],[], '-', color=self.colors[i], label=key)
        legend = self.ax.legend(loc='upper left', shadow=True)
        self.ax.set_autoscale_on(True)
        
    def preprocess_data(self, data):
        x = [ts for reqnum, reqtime, ts in data if reqnum != 0]
        y = [reqtime / reqnum for reqnum, reqtime, ts in data if reqnum != 0]
        return x, y
        
    def update(self, data):        
        for key, values in data.items():
            x, y = self.preprocess_data(values)
            self.lines[key].set_xdata(x)
            self.lines[key].set_ydata(y)
        
        self.ax.relim()
        self.ax.autoscale_view()
        
        self.figure.canvas.draw()
        
init_data = {'a': [], 'b': []}
D = [{'a': [(1, 2, 1), (3, 4, 2), (4, 5, 3)]
      'b': [(5, 6, 1), (7, 8, 2), (9, 10, 3)]},
     {'a': [(3, 4, 2), (4, 5, 3), (5, 6, 4)]
      'b': [(7, 8, 2), (9, 10, 3), (10, 11, 4)]},]
      
plot = DynamicPlot(init_data)
for d in D:
    plot.update(d)