Python list of turtles X coordinate changing automatically

Question

Trying to select and change the color of the turtles that are blocks that are arranged in a 20x20 matrix With the selected blocks I will run the algorithm of Convay's Game of Life

import turtle
from turtle import Turtle, Screen
import os
import random
import time
import math

#setting up the game window

wn=turtle.Screen()
wn.tracer(0)
wn.bgcolor(0,0,0)
wn.title("game_of_life")
wn.colormode(255)
tracker1=turtle.Turtle()
tracker1.speed(0)
tracker1.hideturtle()
tracker1.setpos(400,-400)
tc=(152,146,241)
tracker1.pencolor(tc)
tracker1.seth(90)

n=800
for i in range(0,4):
    tracker1.fd(n)
    tracker1.lt(90)

startk=0

#start key
def startsc():
    global startk
    startk+=1     

#selecting cell life
def selec(x,y):
    global lr
    print("\n\n")
    for n in range(0,20):
        for m in range(0,20):
            x1,y1=lr[i][j].xcor(),lr[i][j].ycor()
            if ((x-x1>=-19 and x-x1<=19) and (y-y1>=-19 and y-y1<=19)):
                lr[i][j].color((0,0,0))
            
def rough():
    print("\n\n")
    for n in range(0,20):
        for m in range(0,20):
            print((n,m))
            print(lr[n][m].pos())       

wn.listen()
wn.onkeypress(startsc,"space")
wn.onkeypress(rough,"Up")
wn.onclick(selec)
class cell(Turtle):
    def __init__(self,life,xc,yc):
        super().__init__(shape='square',visible=True)
        self.color(life)
        #self.shape("square")
        #self.shapesize(2)
        self.speed(0)
        self.penup()
        self.setx(xc)
        self.sety(yc)
        self.showturtle()
    


pen=turtle.Turtle()
pen.speed(0)
pen.shape("square")
pen.hideturtle()
pen.penup()
pen.color("Green")
pen.goto(-300, 150)
txt="Instructions:\n1.Enter the number of cells you want\nto be alive at start, max 8\n2.Select the boxes and the game will \nstart once you have finished your selection."
txl=list(txt)
s=""
i=0
wn.tracer(0)   
while True:
    if startk==0:
        while i<len(txt):
            if startk==0:
                s=s+txt[i]
                pen.clear()
                pen.write(s,font=("Courier", 18, "normal"))
                time.sleep(0.09)
                i+=1
                if (i>(len(txt)-2)):
                    startk=1
            else:
                break
    elif startk==1:
        pen.clear()
        pen.write("Instructions:\n1.Enter the number of cells you want\nto be alive at start, max 8\n2.Select the boxes and the game will \nstart once you have finished your selection.", align="left", font=("Courier", 18, "normal"))
    elif startk==2:
        pen.clear()
        break



lr=[[0]*20]*20
turtle.speed(0)
for i in range(0,20):
    for j in range(0,20):
        kx= -400 +20 + i*40
        ky= 400 -20-j*40
        lr[i][j]=cell((255,255,255),kx,ky)
        print((i,j))
        print(lr[i][j].pos())


        

print("\n")
""" i=15
j=8
print((i,j))
print(lr[i][j].pos())
 """

for i in range(0,20):
    for j in range(0,20):
        print((i,j))
        print(lr[i][j].pos())

wn.tracer(1)

wn.mainloop()

This loop

for i in range(0,20):
    for j in range(0,20):
        kx= -400 +20 + i*40
        ky= 400 -20-j*40
        lr[i][j]=cell((255,255,255),kx,ky)
        print((i,j))
        print(lr[i][j].pos())

and this loop

for i in range(0,20):
    for j in range(0,20):
        print((i,j))
        print(lr[i][j].pos())

print different values for the X coordinate, the X coordinate is printed as a constant in the second loop

score 0 · Answer 1 · answered May 08 '22 at 03:57

Your problem is this line:

lr = [[0]*20]*20

You're ending up with multiple pointers to the last row. Read this answer about "How to initialize a two-dimensional array in Python?" which will lead you to something like:

lr = [[0] * 20 for _ in range(20)]

Python list of turtles X coordinate changing automatically

1 Answers1