[python] How do I bind the enter key to a function in tkinter?

I am a Python beginning self-learner, running on MacOS.

I'm making a program with a text parser GUI in tkinter, where you type a command in a Entry widget, and hit a Button widget, which triggers my parse() funct, ect, printing the results to a Text widget, text-adventure style.

> Circumvent the button

I can't let you do that, Dave.

I'm trying to find a way to get rid of the need to haul the mouse over to the Button every time the user issues a command, but this turned out harder than I thought.

I'm guessing the correct code looks like self.bind('<Return>', self.parse())? But I don't even know where to put it. root, __init__, parse(), and create_widgets() don't want it.

To be clear, the only reason anyone should hit enter in the prog is to trigger parse(), so it doesn't need to be espoused to the Entry widget specifically. Anywhere it works is fine.

In response to 7stud, the basic format:

from tkinter import *
import tkinter.font, random, re

class Application(Frame):
    
    def __init__(self, master):
        Frame.__init__(self, master, ...)
        self.grid()
        self.create_widgets()
        self.start()

        
    def parse(self):
        ...


    def create_widgets(self):
        
        ...

        self.submit = Button(self, text= "Submit Command.", command= self.parse, ...)
        self.submit.grid(...)

        
root = Tk()
root.bind('<Return>', self.parse)

app = Application(root)

root.mainloop()

Another alternative is to use a lambda:

ent.bind("<Return>", (lambda event: name_of_function()))

Full code:

from tkinter import *
from tkinter.messagebox import showinfo

def reply(name):
    showinfo(title="Reply", message = "Hello %s!" % name)


top = Tk()
top.title("Echo")
top.iconbitmap("Iconshock-Folder-Gallery.ico")

Label(top, text="Enter your name:").pack(side=TOP)
ent = Entry(top)
ent.bind("<Return>", (lambda event: reply(ent.get())))
ent.pack(side=TOP)
btn = Button(top,text="Submit", command=(lambda: reply(ent.get())))
btn.pack(side=LEFT)

top.mainloop()

As you can see, creating a lambda function with an unused variable "event" solves the problem.

I found one good thing about using bind is that you get to know the trigger event: something like: "You clicked with event = [ButtonPress event state=Mod1 num=1 x=43 y=20]" due to the code below:

self.submit.bind('<Button-1>', self.parse)
def parse(self, trigger_event):
        print("You clicked with event = {}".format(trigger_event))

Comparing the following two ways of coding a button click:

btn = Button(root, text="Click me to submit", command=(lambda: reply(ent.get())))
btn = Button(root, text="Click me to submit")
btn.bind('<Button-1>', (lambda event: reply(ent.get(), e=event)))
def reply(name, e = None):
    messagebox.showinfo(title="Reply", message = "Hello {0}!\nevent = {1}".format(name, e))

The first one is using the command function which doesn't take an argument, so no event pass-in is possible. The second one is a bind function which can take an event pass-in and print something like "Hello Charles! event = [ButtonPress event state=Mod1 num=1 x=68 y=12]"

We can left click, middle click or right click a mouse which corresponds to the event number of 1, 2 and 3, respectively. Code:

btn = Button(root, text="Click me to submit")
buttonClicks = ["<Button-1>", "<Button-2>", "<Button-3>"]
for bc in buttonClicks:
    btn.bind(bc, lambda e : print("Button clicked with event = {}".format(e.num)))

Output:

Button clicked with event = 1
Button clicked with event = 2
Button clicked with event = 3