One way would be to inherit a new class,EntryWithSet, and defining set method that makes use of delete and insert methods of the Entry class objects:
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
class EntryWithSet(tk.Entry):
"""
A subclass to Entry that has a set method for setting its text to
a given string, much like a Variable class.
"""
def __init__(self, master, *args, **kwargs):
tk.Entry.__init__(self, master, *args, **kwargs)
def set(self, text_string):
"""
Sets the object's text to text_string.
"""
self.delete('0', 'end')
self.insert('0', text_string)
def on_button_click():
import random, string
rand_str = ''.join(random.choice(string.ascii_letters) for _ in range(19))
entry.set(rand_str)
if __name__ == '__main__':
root = tk.Tk()
entry = EntryWithSet(root)
entry.pack()
tk.Button(root, text="Set", command=on_button_click).pack()
tk.mainloop()