1. Let’s Learn 6. Nested Loops Saenthong School, January – February 2016
Teacher: Aj. Andrew Davison, CoE, PSU Hat Yai Campus
6. Nested Loops
Loops inside loops

2. 1. Draw a Line of Stars StarsLine.py A line of stars is one star
printed again
and again.

3. Draw a Block of Stars StarsBlock.py A loop that runs inside another
loop is called
a nested loop
A block of stars
is one star line
printed again
and again.

4. Draw Blocks of Stars StarsBlocks.py Two nested loops:
blocks  block  line
Blocks of stars
are one star block
printed again
and again.

5. 2. Star Steps StarSteps.py The range is 1 to numBlocks Steps of stars
is one star line
printed again
and again, but
with line length
changing

6. Star Steps Showing the Variable
StarStepsVar.py
Star Steps Showing the Variable

7. 3. Mult. Table for 5's
MultTable.py
The range is
1 to 10

8. Multi. Tables for 5, 6, 7 MultTables.py The range is 5 to 8
Multiplication Tables
are one table printed
again and again.

9. 4. Drawing Many Shapes
ShapeInput.py draws 1 shape using 1 loop:

10. If this loop was nested inside a numShapes loop, then many shapes could be printed.
ShapesInput.py

11. A Different Offset
So that we can see each shape, the outer numShapes loop moves the turtle using goto()
this puts the turtle in a new position, but the turtle is still facing East
A different offset would be to rotate the turtle before drawing a shape.

12. ShapesInput.py with Rotation

13. 5. Hot Dog Combinations (combos)
You can make a hot dog in lots of ways:
with/without a sausage (dog)
with/without bread (the bun)
with/without tomato sauce (ketchup)
with/without mustard
with/without onion
Some of these combos are silly.
What are all the possible combos?

14. All the Combos: I always go for combo 29. What about you? What does
combo 1 mean?
How would you eat
combo 7?

15. HotDogCombos.py
Four nested loops

16. HotDogCombos2.py Prints the same as before, but the loops and ifs use
False and True
instead of
0 and 1

17. HotDog Calories
What is the combo with the smallest number of calories?
Combo 29 has 340
calories, which is high.
Combo 1 is the best
for a diet.
What does it mean?

18. HotDogCalories.py
I've switched back
to loops using
0 and 1. Why?