Hi Everyone, I have been learning to use matplotlib in Python for visualisation. There are a few examples already on the hub but from some time ago and therefore using legacy Python nodes. So, I’m just sharing an updated version using the latest Python Scripting nodes, in case they are useful for anyone :slight_smile: Here is the original matplotlib example, that creates a plot with 2 different y-axes, for example: [image] You can find my workflow on the hub here: [image] 20230425 Pikairos Plot with 2 y-axes using Python Scripting Nodes for KNIME... A basic example of how to make a view in python with 2 y-axes using the latest Python Script and Python View Nodes Hope its useful! Thanks Heather

As complementary information, I’m sharing the Python code, so people searching for this type of solution on Google can find it more easily: import knime.scripting.io as knio from io import BytesIO import matplotlib.pyplot as plt import numpy as np import pandas as pd #Plot creation fig, ax1 = plt.subplots() #Input data data = knio.input_tables[0].to_pandas() abs = data[knio.flow_variables['abscissa']] data1 = data[knio.flow_variables['ordinate_1']] data2 = data[knio.flow_variables['ordinate_2']] #Vertical label ax1.set_xlabel(knio.flow_variables['abscissa']) #First plot color choice color = knio.flow_variables['First_plot_color'] #Horizontal label ax1.set_ylabel(knio.flow_variables['ordinate_1'], color=color) #Creation first plot ax1.plot(abs, data1, color=color) #Parameters for first plot ax1.tick_params(axis='y', labelcolor=color) # instantiate a second axes that shares the same x-axis ax2 = ax1.twinx() #Second plot color choice color = knio.flow_variables['Second_plot_color'] #Horizontal label ax2.set_ylabel(knio.flow_variables['ordinate_2'], color=color) #Creation second plot ax2.plot(abs, data2, color=color) #Parameters for second plot ax2.tick_params(axis='y', labelcolor=color) #Plot resizing fig.tight_layout() # otherwise the right y-label is slightly clipped # Create buffer to write into buffer = BytesIO() # write the plot into the buffer ax2.figure.savefig(buffer, format='svg') # The output is the content of the buffer output_image = buffer.getvalue() # Assign the figure to the output_view variable knio.output_view = knio.view(fig) # alternative: knio.view_matplotlib() Best Heather

Plot with 2 y-axes using Python Scripting nodes for KNIME 4.7

KNIME Extensions

mlauber71 April 26, 2023, 3:49pm 2

@HeatherPikairos thank you. You could also take a look at this example

2 Likes