有没有办法在 Python 中使用 f-string 的函数中使用变量？

Question

I have 2 variables n1 and n2 . When I press space randNum is either equal to 1 or 2 and if it is equal to 1 then I want to change n1 and if it is equal to 2 then I want to change n2 . I am using .itemconfig() to change the variable but I do not know how to asign it to the variable that I want to change. I tried to somehow do it with f-string but that does not work. Is there any way to do it? Here is my code:

import tkinter as tk
import random


canvas = tk.Canvas()
canvas.pack()


n1 = canvas.create_text(100, 100, font="Arial 25", text="1")
n2 = canvas.create_text(100, 150, font="Arial 25", text="2")


def function(event):
    if event.keysym == 'space':
        randNum = random.randint(1,2)
        canvas.itemconfig(f"n{randNum}", font="Arial 25", fill="red", text=randNum) #does not work


canvas.bind_all('<Key>', function)


tk.mainloop()

Answer 1

You can use tags option of create_text() :

n1 = canvas.create_text(100, 100, font="Arial 25", text="1", tags="n1")
n2 = canvas.create_text(100, 150, font="Arial 25", text="2", tags="n2")


def function(event):
    if event.keysym == 'space':
        randNum = random.randint(1,2)
        canvas.itemconfig(f"n{randNum}", font="Arial 25", fill="red", text=randNum)

Answer 2

If you wish the text colors to oscillate between black and red then here is one option.

n0 = canvas.create_text(100, 100, font="Arial 25", text="1")
n1 = canvas.create_text(100, 150, font="Arial 25", text="2")

def function(event):
    r  = random.randrange(2)
    c = [ "red", "black" ]
    if r: c.reverse()
    canvas.itemconfig( f"{n0}", fill=c[0] )
    canvas.itemconfig( f"{n1}", fill=c[1] )


canvas.bind_all( '<space>', function )

Answer 3

You need to use tags

import tkinter as tk
import random

def function(event=None):
    rand_num = random.randint(1,2)

    # resetting the color of existing elements
    for i in range(1, 3):
        canvas.itemconfig(f"tag{i}", font="Arial 25", fill="black")

    # highlighting the active one
    canvas.itemconfig(f"tag{rand_num}", font="Arial 25", fill="red")


canvas = tk.Canvas()
canvas.pack()

n1 = canvas.create_text(100, 100, font="Arial 25", text="1", tags="tag1")
n2 = canvas.create_text(100, 150, font="Arial 25", text="2", tags="tag2")

canvas.bind_all('<space>', function)

tk.mainloop()