How to move a turtle stamp in python

Question

How do I move a stamp in python turtle module?

Here's my code so far:

import turtle

def draw_start():
    turtle.pu()
    turtle.setpos(-350,300)
    turtle.pendown()
    turtle.right(90)
    turtle.forward(520)


def draw_finish():
    turtle.speed(15)
    turtle.pu()
    for i in range(18):
        turtle.setpos(200,(300-(i*30)))
        square()
    for j in range(18):
        turtle.setpos(215,(285-(j*30)))
        square()

def stamp_turtle(x,y,color):
    turtle.pu()
    turtle.setheading(0)
    turtle.shape("turtle")
    turtle.color(color)
    turtle.setpos(x,y)
    stamp_list.append(turtle.stamp())

def square():
    turtle.pu()
    turtle.fill(True)    
    for i in range(4):
        turtle.forward(15)
        turtle.right(90)
    turtle.fill(False)

print "Welcome to Turtle Racing : "
number_of_turtles = int(raw_input("How many turtles (between 3 and 6) : "))
bet_amount = int(raw_input("How much do you want to bet? $ "))
bet_turtle = raw_input("Which turtle (1 to 5)? ")

color_list=["red","blue","green","brown","yellow","purple"]
stamp_list=[]
draw_start()
draw_finish()
for i in range(number_of_turtles):
    stamp_turtle(-370,280-i*90,color_list[i])`

Answer 1

The answer is you don't move stamps, you move turtles! Stamps have to be removed and restamped whereas turtles can move without redrawing:

import random
import turtle

STAMP_SIZE = 20
SQUARE_SIZE = 15
FINISH_LINE = 200
COLOR_LIST = ['red', 'blue', 'green', 'brown', 'yellow', 'purple']

def draw_start():
    turtle.speed('fastest')
    turtle.penup()
    turtle.setpos(-350, 300)
    turtle.pendown()
    turtle.right(90)
    turtle.forward(520)

def draw_finish():
    turtle.shape('square')
    turtle.shapesize(SQUARE_SIZE / STAMP_SIZE)
    turtle.penup()

    for i in range(18):
        turtle.setpos(FINISH_LINE, (300 - (i * SQUARE_SIZE * 2)))
        turtle.stamp()

    for j in range(18):
        turtle.setpos(FINISH_LINE + SQUARE_SIZE, ((300 - SQUARE_SIZE) - (j * SQUARE_SIZE  * 2)))
        turtle.stamp()

    turtle.hideturtle()

def move_turtle(who):
    who.forward(random.randint(1, 10))
    if who.xcor() < FINISH_LINE:
        turtle.ontimer(lambda who=who: move_turtle(who), 50)

print('Welcome to Turtle Racing!')
number_of_turtles = int(input('How many turtles (between 3 and 6): '))

draw_start()
draw_finish()

turtle_list = []

for idx in range(number_of_turtles):
    racer = turtle.Turtle('turtle', visible=False)
    racer.speed('fastest')  # affects drawing speed, not forward motion
    racer.penup()
    racer.setpos(-350 - STAMP_SIZE, 280 - idx * 90)
    racer.color(COLOR_LIST[idx])
    racer.showturtle()

    turtle_list.append(racer)

for racer in turtle_list:
    turtle.ontimer(lambda who=racer: move_turtle(who), 100)

turtle.exitonclick()

The place where stamping speeds things up is in making your finish line which takes much longer if you try to draw it.

Note that although your original code is Python 2, my answer is Python 3 so you may need to tweak a couple of things if you're still using the older version.