1. For vs. While loop count=0 while count< 5: for count in range(5):
name=input(‘Guess my name.\n’)
if name==‘kim’:
break
count= count+1
for count in range(5):
name=input(‘Guess my name.\n’)
if name==‘kim’:
break

2. “for” loop p=min true false for p in range(min, max, interval): block
p >= max
false
Do block
p = p + interval
Out of “for”

3. turtle module Simple graphics programming How to use it ?
Import ‘turtle’ module by including
from turtle import *
Need to create a turtle, and NAME it to manipulate
Say, you named a turtle ‘xxx.’
xxx = Turtle() or Pen()
Opens up a turtle window
Can have more than one turtles at a time – tell them apart by names

4. turtle module >>> import turtle
>>> myT = turtle.Turtle()
What is “.” between turtle and Turtle() ?
turtle => class (generic object referring to turtle module)
Turtle() => method (action, function, constructor)
Rough interpretation: get ‘turtle’ type (class) and do ‘Turtle()’
>>> myT.color(“red”)
Get ‘myT’ turtle and color it red
Attribute
Position, heading (direction), color, tail position

5. Turtle in Python Actions References With myT
myT.forward(100), myT.backward(100)
myT.right(90), myT.left(45)
myT.goto(-200,90), myT.circle(50), myT.color(“red”)
myT.up(), myT.down()
myT.write(“Hello!”)
References
Official Python turtle page

6. Figure 1.9

7. Which methods to use ? Suppose ‘myT’ turtle is created
Draw a circle myT.circle(100)
Draw a thicker circle – myT.width(5)
Find out the location (x,y) of myT – myT.position()
Move myT to (100,-50) – myT.goto(100,-50)
Stop drawing – myT.up()
Find out the screen sizes
screen=myT.getscreen()
screen.window_width() and screen.window_height()

8. HW 2: due 9/23 (Fri) Draw olympics rings
penup()
Goto a location
pendown()
Draw a circle
Take the screen shot which includes your python codes and the drawing to

9. While Function eval() returns the result of an arithmetic operation
For the English description below, write Python function (and a call to the function)
Ask to enter a simple arithmetic operation or ‘q’ to stop
As long as the input is not ‘q’
print the result of the arithmetic operation
Ask the same question again

10. Iteration – drunken turle
Random walk or Brownian motion
A turtle
From the current position
Take an arbitrary direction and distance as the next position
Goto the next position
Next position becomes the current position next time around

11. Random package import random
random.randint(100) returns a random integer
How to get a random number between (0,100)?
A random number between (-50, 50) ?

12. Drunken Turtle With For loop
Create a turtle, name it on your own
For 200 times, repeat
Get the distance to the next random position from (curX, curY)
Add the distance to (curX, curY) to compute the new random location
Move the turtle to the new location

13. Lab 0919 Write a Python program to simulate a drunken turtle
Modify the drunken turtle program so that the turtle stays in bound
wn = turtle.getscreen()
wWid = wn.window_width()
wHgt = wn.window_height()
Make it sure that you halve the window sizes for +- coordinates
your Python program