I am attempting to store coordinates from two mouse clicks in an interactive matplotlib graph in JupyterLab. I have managed to interact with the plot and get the x and y coordinates to print upon clicking. However, when I try to store those coordinates by appending to a list or numpy array (tried both), the values are not saving in my global variable coords. Since I can get the coordinates for one click successfully as ix and iy, I suppose I could have duplicate cells each with one click event each, but I'd prefer to have a single cell that can store both clicks' coordinates. My original code was taken from this question. I have had to make a few adjustments to work with ipympl and ipywidgets. Specifically, coords prints as empty even though my if statement regarding its length does seem to terminate the click event. Maybe I am missing something obvious (I am relatively new to Python from a MATLAB background). I'd appreciate any advice or alternative approaches to the issue. %matplotlib ipympl import pandas as pd import numpy as np import matplotlib.pyplot as plt from scipy.optimize import curve_fit from scipy import stats import os import ipywidgets as widgets out = widgets.Output() coords = [] fig, ax = plt.subplots(figsize =(4, 4)) ax.plot(time,temp,'k-',linewidth = 1.5) ax.set_xlabel("Time (sec)") ax.set_ylabel(r"Temperature ($\degree$ C)") ax.tick_params(axis="both",direction='in',top=True, right=True) plt.show() @out.capture() def onclick(event): ix, iy = event.xdata, event.ydata print ('x = ',ix, 'y = ',iy) global coords coords.append(ix) coords.append(iy) # Disconnect after 2 clicks if len(coords) == 4: fig.canvas.mpl_disconnect(cid) return coords cid = fig.canvas.mpl_connect('button_press_event', onclick) display(out) print(coords) image of interactive figure and printed coordinates, for reference Continue reading...
