Printing characters(with delay) on the same widget multiple times in Tkinter - user-interface

Question

I'm trying to print with delay (one character appears, a few milliseconds pass and then the next one appears) on the same widget multiple times one after the other, being something like >text appears with delay > a second passes> more text appears with delay... and so on. time.sleep() doesn't seems to work and i don't know how to properly use .after()
Here's the code i'm using
from tkinter import *
def insert_slow(widget, string):
if len(string) > 0:
widget.insert(END, string[0])
if len(string) > 1:
widget.after(50, insert_slow, widget, string[1:])
root=Tk()
tx=Text(root)
tx.pack()
insert_slow(tx, "this is a testing piece of text\n")
tx.after(3000)
loop=insert_slow(tx, "this is another testing piece of text")
root.mainloop()

Answer 1

The problem with your code is that after(3000) is almost exactly the same as time.sleep -- it freezes the whole UI.
The solution is pretty simple: use after to call your second insert_slow.
insert_slow(tx, "this is a testing piece of text\n")
tx.after(3000, insert_slow, tx, "this is another testing piece of text")
However, you need to be aware that after is relative to the time that you call after. Since the second line of code in the above example runs just a millisecond after the first, the second invocation won't happen 3 seconds after the first string appears, it will happen 3 seconds after it starts to appear.
If you want to wait for the first one to finish and then wait three seconds, you'll either have to do the math yourself (add 50ms times the number of characters to the starting value), or add some other mechanism. You could pass multiple strings to insert_slow, and it could automatically wait three seconds between each string.

Answer 2

Your code is executing the both texts in parallel so you get this output:
text1 = 'Hi to you'
text2 = 'Hi to me'
OUTPUT:
HHii tt oo ymoeu
Your insert_slow behaves well but you dont need to use after() again if you try to run text in two separate lines.
And if so, this should be on a different new text widget.
This code works if you want to output text on the same widget:
from tkinter import *
def insert_slow(widget, string):
if len(string) > 0:
widget.insert(END, string[0])
if len(string) > 1:
widget.after(50, insert_slow, widget, string[1:])
root=Tk()
tx=Text(root)
tx.pack()
text_body = "this is a testing piece of text\n" \
"this is another testing piece of text"
insert_slow(tx, text_body)
root.mainloop()
if you want the text lines to insert slow together, you can use this also:
from tkinter import *
def insert_slow(widget, string):
if len(string) > 0:
widget.insert(END, string[0])
if len(string) > 1:
widget.after(50, insert_slow, widget, string[1:])
root=Tk()
tx1=Text(root)
tx2=Text(root)
tx1.pack()
tx2.pack()
text_body1 = "this is a testing piece of text\n"
text_body2 = "this is another testing piece of text"
insert_slow(tx1, text_body1)
insert_slow(tx2, text_body2)
root.mainloop()