How to continuously send an array of serial data into multiple functions, with the data being updated everywhere?

Question

I want to code a script, that has several different functions in which an array filled with serial data has to be received. The serial data comes from an arduino every 1 seconds. (don't worry. I changed the code to a reproducible example by using a random array.)

What I've succeeded in so far is, that the code does send the array into the function example ONCE the first time and displays it as I want it to.

What it does not do yet, is, that the information inside the function gets updated as it comes in from the arduino. When you see the code, you're gonna say, well the data is only sent once. BUT when I randomize the array every second inside a loop, the loop obviously blocks the rest of the code and the gui won't build. The fact is, that serial read updates the array WITHOUT a loop, which is highly appreciated.

The question is: How do I transport this updating into the function. Remember: It would be the natural solution for the code below to simply insert the serial read stuff INSIDE the function. BUT this is just the code that boils down the issue. The real code has several widgets invoked inside several functions and I ended up copy-&-pasting THE ENTIRE serial data signal conditioning code block into EVERY function that needs the data. This significantly increased the lag of the code, and thus is no solution.

The example script contains commented out sections to make it easier to follow what I've been trying to do to solve it so far:

import numpy as np
#import rhinoscriptsyntax as rs
import time
import tkinter as tk
import serial

"""
ser = serial.Serial(
 port='/dev/ttyUSB0',
 baudrate = 500000,
 #parity=serial.PARITY_NONE,
 #stopbits=serial.STOPBITS_ONE,
 #bytesize=serial.EIGHTBITS,
 timeout=1
)
ser.flushInput()
ser.flushOutput()

#I've been trying to embed the serial read stuff inside a function itself, which I'd LOVE to implement,
#but it has the same problem: either it is called just once as it is written here, ore a loop blocks the code

def serial_data():
    #serialData = ser.readline()
    #serialData = serialData.decode()
    #floats = [float(value) for value in serialData.split(',')]
    #arr = np.array(floats)
    arr = np.random.rand(100)
    time.sleep(1)
    return arr
"""
#above commented out and replaced with random array below. 
#serialData = ser.readline()
#serialData = serialData.decode()
#floats = [float(value) for value in serialData.split(',')]
#arr = np.array(floats)

arr = np.random.rand(100)
time.sleep(1)
print(np.round(arr, 3))

def nextWindow(root):
    frame1 = tk.Frame(root, width=800, height=500)
    frame1.pack()
    text= tk.Text(frame1, width=80, height= 12, bd=0)
    text.pack()
    text.delete("1.0",tk.END)
    #serialData = serial_data()
    #text.insert(tk.INSERT, serialData)
    text.insert(tk.INSERT, np.round(arr, 3))
    text.update()

root = tk.Tk()
root.title('PythonGuides')
root.geometry('300x200')
root.config(bg='#4a7a8c')
nextWindow(root)

root.mainloop()

Answer 1

A minimal example as to how to use .after "loops" (explanation in code comments):

import tkinter as tk

# for the example
counter = 1


# your serial_data function, renamed to
# be more self-explanatory
def get_serial_data():
    # put the serial reading stuff here
    # the counter is just an example
    global counter
    counter += 1
    return str(counter)


def update_text(txt):
    # get data, clear text widget, insert new data
    serial_data = get_serial_data()
    txt.delete('0.0', 'end')
    txt.insert('end', serial_data)
    # schedule this function to run again in 100ms
    # so it will repeat all of this effectively
    # updating the text widget, you don't need to call `.update`
    # note that this is not recursive
    root.after(100, update_text)


def create_text():
    text = tk.Text(root)
    text.pack()
    update_text(text)


root = tk.Tk()

create_text()

root.mainloop()