如何使用随机模块在三个字符串之间进行选择？

Question

So this program prints 30 concentric circles in the middle of my canvas, I am trying to make each circle a random color using a function that I have to call, I don't really know why this doesn't work. Can you tell me: A. Why doesn't this work the way it is now? B. How can I fix it?

from tkinter import *
from random import *
root = Tk()

w, h = 800, 600
c = Canvas(root, width=w, height=h, bg="gold")
c.pack()

so this is the part that I need help with:

def colors(r = "Red", p = "Purple", b = "Blue"):
    for i in range(0, 3):
        choice([r, p, b])


colors("Red","Purple","Blue")
    

And also need help with calling the function

cx, cy = w//2, h//2
z = 5
for _ in range(30):
    c.create_oval(cx-z, cy-z, cx+z, cy+z, width=2, outline = colors(r, p, b))                                                           
    z += 5

Thanks a lot!

full code:

from tkinter import *
from random import *
root = Tk()

w, h = 800, 600
c = Canvas(root, width=w, height=h, bg="gold")
c.pack()


def random_colors(r = "Red", p = "Purple", b = "Blue"):
    for i in range(0, 3):
        choice([r, p, b])


random_colors("Red","Purple","Blue")
    
cx, cy = w//2, h//2
z = 5
for _ in range(30):
    c.create_oval(cx-z, cy-z, cx+z, cy+z, width=2, outline = choice([r,p,b])
z+= 5

root.mainloop()

Answer 1

Let us try random.choice :

In [28]: from random import *
    ...:
    ...: def random_colors(r, p, b):
    ...:     r = "Red"
    ...:     p = "Purple"
    ...:     b = "Blue"
    ...:     for i in range(0, 3):
    ...:         print(choice([r, p, b]))
    ...:
    ...: random_colors("Red","Purple","Blue")
Purple
Red
Red

And are you looking for default values?

from random import *

def random_colors(r = "Red", p = "Purple", b = "Blue"):
    for i in range(0, 3):
        print(choice([r, p, b]))

random_colors("Red","Purple","Blue")

Answer 2

I think you can make this better by passing your own colors as arguments

from tkinter import *
from random import choice

root = Tk()

w, h = 800, 600
c = Canvas(root, width=w, height=h, bg="gold")
c.pack()

def colors(*args):
    default = ['red','purple','blue'] # main set of colors
    args = [_ for _ in args] # custom passed color
    color_lst = args + default # list of all colors passed and default
    color = choice(color_lst) #choosing a random color from the list
    return color #returning the color
    
cx, cy = w//2, h//2
z = 5
for _ in range(30):
    c.create_oval(cx-z, cy-z, cx+z, cy+z, width=2, outline = colors('orange','white'))  #calling the function with extra 2 colors                                                          
    z += 5

root.mainloop()

I've explained it with comments to make you understand while reading it. Also its better to say from random import choice or import random because or else it might pollute your namespace.