Lets Learn Python and Pygame Aj Andrew Davison

Let's Learn Python and Pygame Aj. Andrew Davison, Co. E, PSU Hat Yai Campus E-mail: ad@fivedots. coe. psu. ac. th 5. Loops Make a program do things over-and-over-and over again. Counting loops; Conditional loops. Games: guessing, ghost, hangman. 1

1. Counting Loop 1. py 2

Using the Counting Loop Variable Loop 2. py The [ … ] is called a list. More later 3

Using the Counting Loop Var. Loop 3. py 4

Coolest. py Counting without Numbers A list can contain anything, not just numbers 5

Loop 4. py Counting Loop Using a Range Less typing, but it goes from 1 to 4 6

Eight Times Table Eight. Times. py This range goes from 1 to 10 7

Blast. Off. py Range with a Step Amount This range goes from 10 to 1 in a step of -1 This program took 10 secs to run. 8

2. Drawing a Turtle Square from turtle import Turtle t = Turtle() t. forward(100) t. right(90) This is Square. py from the Modules slides. The forward() and right() code is repeated four times. A loop will make this code smaller, and easier to change. 9

Square. py with a Loop 10

Square 1. py with Variables The variables make it easy to change the code. What if num. Sides == 3 and angle = 120? 11

Shape. py 12

Connect No. Sides and Angle §For a square, num. Sides == 4, angle == 90 §For a triangle, num. Sides == 3, angle == 120 §The math connection: § num. Sides * angle == 360 §Test it. A 5 -sided shape (pentagon) means: § 5 * angle == 360 § so angle = 360/5 13

Revised Shape. py 14

Make Shape Code Easier to Use §In Shape. Input. py § read in the num. Sides data using the turtle command numinput() § calculate the angle using the num. Sides data 15

Shape. Input. py 16

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A Square Spiral Square. Spiral 1. py 18

Square. Spiral 3. py Square (90 91 ) + Color no need to write 1. . 100 19

Square Circle 20

Color. Square. Spiral. py Square Spiral Again with different colors 21

3. Conditional Loops §A conditional loop uses a test to decide when to stop looping § the same kind of test as in "if" 22

Eight Times Table Again While. Less. py i < 11 is the test the while body is run over and over most while body's need to include an increment 23

Flowchart for Conditional Loop program execution i=1 i < 11? no; so finish yes; keep going loop back. action i=i+1 execution continues. . . 24

While. Prob. py Eight Times Table Problem I typed ctrl-c i never changes because there is no increment. This means i never reaches 11 and so the loop never ends. 25

While that Likes "3" While 3. py 26

Breaker. py Using break in a Loop break makes Python leave the loop 27

Guessing. Game. py 4. A Number Guessing Game 28

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Uses two modules; a while loop; if tests 31