1. While loop Get names up to five times count=0 while count< 5:
name=input(‘Guess my name.\n’)
if name==‘kim’:
break
count= count+1

2. For loop Convenient when the number of iterations is known count=0
while count< 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

3. FOR loop “for i in range(max):”
“i” is a dummy variable keeping counts in the range
“i” starts at 0, increments by 1, and ends at (max-1)
max=4: i=0, 1, 2, 3
Block of statements (instructions) to be repeats is indented
“:” at the end of “for”

4. General FOR loop “for i in range(min, max, interval):” “i”
“i” = min
min+interval
min+interval+inteval ….
“inteval” is omitted if interval==1

5. More about ‘for’ loop What will be printed x=0 for i in range(3):
x=x+1
print(x)
for x in range(0,3):
x=x+1
print(x)
for i in range(-2,3):
print(i)
for count in range(5,-5,-2):
print(count)

6. “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”

7. Importing modules
Modules are pre-programmed package including useful tools/resources
math
bioPython
pyGame

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

9. 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

10. 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

11. Figure 1.9

12. 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()

13. 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