For the Pygal line graph, we can largely follow the same pattern as our Matplotlib example, where we create lists of values by reading the file. We no longer need to convert the x axis value into an internal float, as we did for Matplotlib; however, we do need to convert the numbers in each of the values we would have received in the float:

  with open('results.txt', 'r') as f:
      for line in f.readlines():
          line = eval(line)
          x_time.append(line['Time'])
          out_packets.append(float(line['Gig0-0_Out_uPackets']))
          out_octets.append(float(line['Gig0-0_Out_Octet']))
          in_packets.append(float(line['Gig0-0_In_uPackets']))
          in_octets.append(float(line['Gig0-0_In_Octet']))

We can use the same mechanism that we saw to construct the line graph:

  line_chart = pygal.Line()
  line_chart.title = "Router 1 Gig0/0"
  line_chart.x_labels = x_time
  line_chart.add('out_octets', out_octets)
  line_chart.add('out_packets', out_packets)
  line_chart.add('in_octets', in_octets)
  line_chart.add('in_packets', in_packets)
  line_chart.render_to_file('pygal_example_2.svg')

The outcome is similar to what we have already seen, but this result is in SVG format that is easier for displaying on a web page. It can be viewed from a browser as follows:

Just like Matplotlib, Pygal provides many more options for graphs. For example, to regraph the pie chart we saw before in Pygal, we can use the pygal.Pie() object:

#!/usr/bin/env python3

import pygal

line_chart = pygal.Pie()
line_chart.title = "Protocol Breakdown"
line_chart.add('TCP', 15)
line_chart.add('UDP', 30)
line_chart.add('ICMP', 45)
line_chart.add('Others', 10)
line_chart.render_to_file('pygal_example_3.svg')

The resulting SVG file would be similar to the PNG generated by Matplotlib: