How do you get a different value for a label each time a button is pressed in `tkinter`?

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So I'm making a random name generator. Everything is pretty much finished in my GUI. The problem is I can only press my generate button once to get all the values that are needed. How can I press the button infinite amount of times, getting different values each time the button is pressed.

Do I need to make a loop of some sort? I put a lambda in there. That holds back the values from just showing on my screen as soon as you open the GUI. This way you can press the button and text appears like normal. 

firstnameli = ['Chris ', 'Kevin ', 'Jeff ', 'Marty ', 'Dolen ']
lastnameli = ['Smith', 'Miller', 'Jones', 'Davis', 'Brown']

full_name = random.choice(firstnameli) + random.choice(lastnameli)

#this allows text to be put in the text box
estr = StringVar()
estr.set(full_name)

fullnameentry = Entry(MyWin, borderwidth=5, font=("Helvetica", 15))

def buttonfunc():
    fullnameentry.config(text=estr)

genbutton = Button(MyWin, text="GENERATE", activebackground="blue", command= lambda: buttonfunc())
command button tkinter python
1 Answers

You generate the random name only once. From then on estr is always going to be the same value.

If you're comfortable with lambda you can use that to make full_name into a function:

full_name = lambda: random.choice(firstnameli) + random.choice(lastnameli)

Afterwards, you'll have to call full_name since it's not a simple string variable anymore but a function:

estr.set(full_name())

Also, you seem to miss setting textvariable=estr for fullnameentry.

Everything put together:

firstnameli = ['Chris ', 'Kevin ', 'Jeff ', 'Marty ', 'Dolen ']
lastnameli = ['Smith', 'Miller', 'Jones', 'Davis', 'Brown']

full_name = lambda: random.choice(firstnameli) + random.choice(lastnameli)

#this allows text to be put in the text box
estr = StringVar()
estr.set(full_name())

fullnameentry = Entry(MyWin, textvariable=estr, borderwidth=5, font=("Helvetica", 15))

def buttonfunc():
    estr.set(full_name())

genbutton = Button(MyWin, text="GENERATE", activebackground="blue", command=buttonfunc)

I also think your code might be a little bit too complicated at some points. Here is a minimal and complete tkinter example, maybe this will help you in some way:

import tkinter as tk
import random

def random_name():
    first_names = ['Chris', 'Kevin', 'Jeff', 'Marty', 'Dolen']
    last_names = ['Smith', 'Miller', 'Jones', 'Davis', 'Brown']
    full_name = '{} {}'.format(random.choice(first_names), random.choice(last_names))
    return full_name

def update_label_and_entry():
    new_random_name = random_name()
    label.config(text=new_random_name)
    entry.delete(0, tk.END) # delete content from 0 to end
    entry.insert(0, new_random_name) # insert new_random_name at position 0

root = tk.Tk()
label = tk.Label(root)
label.pack()
entry = tk.Entry(root)
entry.pack()
button = tk.Button(root, text="New random name", command=update_label_and_entry)
button.pack()
root.mainloop()

Of course, this code is not perfect. The code could be improved further for example by moving first_names and last_names to a global namespace, so other methods can access the values, too. Also, you could write a class for your window or for the label which will include the update_label method.

user_16210410
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