Flash card challenge

Project
Write a flash card quizzer from scratch.

Goals

 * practice breaking down a problem and solving it in Python from scratch
 * practice command line option parsing
 * practice reading from files
 * practice working with dictionaries and for loops

Problem statement
Write a Python script that takes a file as an argument and quizzes the user based on the contents of that file until the user quits the program. Questions should be selected randomly (as opposed to going in order through the file), and the user should type in their guess. The script should say whether or not a guess is correct and provide the correct answer if an incorrect answer is given.

The file will contain flash card challenges in the form:

question,answer question,answer question,answer question,answer ...

For example, a state capitals flash card file might have the form:

Alabama,Montgomery Alaska,Juneau Arizona,Phoenix ...

Running the quizzer script with this file might look like this:

$ python quizzer.py state_capitals.txt Texas? Austin Correct! Nice job. New Mexico? Santa Fe Correct! Nice job. Oregon? Portland Incorrect. The correct answer is Salem. Virginia? Richmond Correct! Nice job. Virginia? Exit Goodbye

1. Learn about HSV values
Run the ColorWall effects again with

python run.py -a

The names of the effects are printed to the terminal as they are run. Pay particular attention to the first 4 effects:
 * SolidColorTest
 * HueTest
 * SaturationTest
 * ValueTest

In all of these effects, a tuple  containing the hue, saturation, and value describing a color are passed to   to change the color of a single pixel on the wall.

What are the differences between these tests? Given these difference and how they are expressed visually, how does varying hue, saturation, or value change a color?

Check your understanding: what saturation and value would you guess firetruck red have?

2. Examine and the interface its subclasses provide
All of the effects inherit from the  class. Examine this class and its  and   methods.

What is the purpose of the  method?

What is the purpose of the  method?

Open up  and look at this chunk of code at the bottom of the file:

for effect in effects_to_run: new_effect = effect(wall) print new_effect.__class__.__name__ new_effect.run

exports and  list at the bottom of the file. goes through every effect in that list, creates a new instance of the effect, and invokes its  method.

Check your understanding: what would happen if you added an effect to the  list that didn't implement a   method? (Try it!)

3. Examine the nested loop in
for x in range(self.wall.width): for y in range(self.wall.height): self.wall.set_pixel(x, y, hsv)

This code loops over every pixel in the ColorWall, setting the pixel to a particular  value. After that  loop is over,   updates the display.

Check your understanding: what would happen if you moved the  to inside the inner   loop, just under   in  ? (Try it!)

Tip: you can run individual tests by passing their names as command line arguments to. For example, if you only wanted to run, you could:

python run.py SaturationTest

4. Implement a new effect called
It should run for 5 seconds, cycling through the colors in the rainbow, pausing for a moment at each color.

Remember to add your effect to the  list at the bottom of  !

Test your new effect with

python run.py RainbowTest

5. Play with the randomness in
Walk through. Find explanations of the  and   functions in the online documentation at http://docs.python.org/library/random.html.

Experiment with these functions at a Python prompt:

import random random.randint(0, 1) random.randint(0, 5) random.uniform(-1, 1)

Then experiment with the numbers that make up the hue and re-run the effect:

python run.py Twinkle

Challenge: make  twinkle with shades of red.

6. Implement a new effect that involves randomness!
Remember to add your effect to the  list at the bottom of.

Checkerboard
Find and change the colors used in the  effect, and re-run the effect:

python run.py Checkerboards

Then change the line

if (x + y + i) % 2 == 0:

to

if (x + y + i) % 3 == 0:

re-run the effect, and see what changed.

What other patterns can you create by tweaking the math for this effect?

Matrix
Find and change the color of the columns in the  effect, and re-run the effect:

python run.py Matrix

Each column that we see on the wall corresponds to a  object. Add some randomness to the color used by each column (the variable whose value you changed above) using the  function, re-run the effect, and see what happens.

Write more of your own effects!
You have color, time, randomness, letters, and more at your disposal. Go nuts!