[Python] How to address line (or similar) elements in a matplotlib window

How do I address a matplotlib element in a window? In this code, a window is created and three lines a re drawn. with the "m" key you can add another line, "l" lists all lines with its position and "n" changes all lines of a certain position to a fixed new one. Just for my education purpose. How do I address a line? I would like to get a lines address f.e. when I hover the mouse pointer over it and change its properties later.

import sys
import matplotlib.pyplot as plt
import matplotlib
import numpy as np

#print relevant info to terminal

Taste = "a"
Vorgang = "a" + " :"

def on_press(event): #get the key pressed and store it in a global variable
global Taste, Vorgang
print("you pressed: ", event.name, " Key: ", event.key, " location: ", event.xdata, event.ydata)
Taste = event.key
Vorgang = event.name + " on_press-test"
print ("Taste: ", Taste, "Vorgang: ", Vorgang, "event.key Type: ",type(event.key), "Taste type: ", type(Taste))

# cretae window with axis and plot lines
fig, ax = plt.subplots(1,1)
fig.canvas.mpl_connect('key_press_event', on_press)
ax = plt.gca()
plt.plot([1.6, 2.7], [1.5, 6.4])
plt.title("interactive test")
plt.xlabel("index")
ax.plot([5.1, 7.2])
ax.plot([3.1, 2.2])

# get all lines and print them to terminal
for x in ax.get_lines():
print (x, " - ", "0.0: ", x.get_xydata()[0,0], "|- 0.1: ", x.get_xydata()[0,1], "|- 1.0: ", x.get_xydata()[1,0], "|- 1.1: ", x.get_xydata()[1,1],)
print (ax.tables)

#start interactive mode and show plot
plt.ion()
plt.show()

#list all plot elements
print ("Start==========================")
for x in fig.axes:
print (ax.lines)
print (x)
print("1st layer")
for line in ax.lines:
print ("x-data ",line.get_xdata())
print ("y-data ",line.get_ydata())
# print (dir(line)) # use only to read modules
print (matplotlib.lines.Line2D)

#loop to react on keys pressed
while True:
if plt.waitforbuttonpress():
print("Test-if1: ", Taste, " Vorgang: ",Vorgang)
if Taste == "Q" or Taste == "q": #quit app
print ("Quit!")
sys.exit()
if Taste =="m": #add another line on a fixed position
ax.plot([2.1, 6.2],[4.3,2.8])
plt.draw()
if Taste =="n": #move added line to a new position
for line in ax.lines:
Xdata = line.get_xdata()
Ydata = line.get_ydata()
print (Xdata, Ydata, "type Xdata: ", type(Xdata), len(Xdata), " ;; ", line.get_xdata())
a = np.array([2.1, 6.2])
print ("a: ", type(a), a.dtype)
if np.array_equal(Xdata,a):
line.set_xdata([2.6, 0.7])
line.set_ydata([1, 2])
plt.draw()
if Taste =="l": #list all lines positions
plt.draw()
for line in ax.lines:
Xdata = line.get_xdata()
Ydata = line.get_ydata()
print (Xdata, Ydata, "type Xdata: ", type(Xdata), len(Xdata), " ;; ", line.get_xdata())
plt.draw()


# to end app.
plt.ioff()
plt.show()


The command print (ax.axes.lines.index) gives:

axes.lines.index <
​

following line gives this answer but not the actual address: print (ax.axes.lines.index)

result:

<Axes.ArtistList of 3 lines> Axes(0.125,0.11;0.775x0.77)
​

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