AP Computer Science 2008-9

1. Download the google app engine stuff for your computer: http://code.google.com/appengine/
You’ll eventually need to get a google account if you don’t already have one in order to upload your applications to the real intertubes.

2. The text recommends a firefox plugin called firebug (download from here).  I recommend both using Firefox and installing Firebug.  However, it becomes more helpful the more you know about web development and various web protocols (which you don’t at this point, but you will!).  Still, it’s helpful to have.

3. ASSIGNMENT - Due: Wed. June 3:

Make bike wattage a google appengine app.  Please make it spiffy.  Here’s what I mean by that:

a. allow the user to specify any/all of the variables involved.  (Do something like have the user only fill in the variables she wants to specify, and then your code determines what’s left blank and calculate it.)

b. make it look good.  Pretty colors, clean and nice styles.

c. Explore the various elements that can be a part of the HTML form tags.  Many of the input components have several attributes and parameters that can be helpful.

3.* If you want to go above and beyond check out the examples given starting on page 93 of the text — related to Multipart POST data.  This allows you to upload plain text files.  If you do this, you should be able to upload two text files and run it through your document similarity code, and produce a number of hits between the two documents.  The hardest part about this is experimenting with Multipart POST data.  Just go slowing and print stuff out as you go.

Posted on May 29th, 2009 by Baker Franke
Filed under: Labs | No Comments »

Scholars,

Your assignment is to produce the top 10 words from decl.txt.  The algorthim is this:

1.
for each word in the file
if the word does not exist in the dictionary
put the word into a dictionary with a value of 1
else
increment the value associated with the word

2.

invert the dictionary
so instead of word->count  mappings, it will contain count->[list,of,words,with,this,count]

3.

sort the keys of the inverted dictionary

print out the words associated with the 10 highest values

NOTE: this is not the only way to do this in python, but I want you to have practice doing the dictionary inversion, sorting the keys, etc.

CODE FROM CLASS

1.  The code I wrote in class…more or less, with comments

#I.O. library
import os

#open a file for reading
fp = open(”path/to/file/file.txt”, “r”)

#iterate through each line

for line in fp:
line = line.replace(”\n”,”")
line = line.replace(”,”, “”)
line = line.lower()

#line.split returns a list, so you can put it right into a loop
for word in line.split(” “):
print word

# of course, you’ll do more than print the word, you’ll add it to a dictionary with the proper count, etc.

HINTS AND ALTERNATIVES:
There is a faster way to read the file.  You can just read it all out into one big string.  That way you don’t have to go through the song and dance of processing each line.  Just do this…

fp = open(”path/to/file/file.txt”, “r”)
fullText = fp.read()
fp.close()

fullText is now a string of the whole file.

Also here is a shortcut for stripping all the punctuation except the words….

import re
fullText = re.sub(”[^a-z' ]“,”",fullText.lower())

NOTE: there is a blank space after the apostrophe (’) and before the ] in the first argument.  What this says is: “for every character in fullText.lower(), if the character is NOT a through z, an apostrophe, or a blank space, then replace it with an empty string.”

Finally, to make a list of all the words, it can be accomplished in basically one line thusly:

import os
import re

fp = open(”path/to/file.txt”, “r”)
allWords = re.sub(”[^a-z' ]“,”",fp2.read().lower()).split(” “)
fp.close()

Posted on May 19th, 2009 by Baker Franke
Filed under: Labs | No Comments »

This is the last lab assignment of APCS

Assignment Sheet:
Lab22_CatchingPlagiarists.pdf [If you CARE ABOUT YOUR GRADE, you'll read the assignment sheet carefully.  Especially the descriptions of each grading Milestone.]

Document Sets:

• Lab22_bigDocSet.zip - 1,354 docs — ~1,615,193 words
• Lab22_medDocSet.zip - 75 docs — ~91,273 words
• Lab22_smDocSet.zip - 25 docs — ~33,946 words

Posted on April 27th, 2009 by Baker Franke
Filed under: Labs | No Comments »

We discussed Lab 20 at length in class.  Here is a copy of the problem statement I handed out….

Handout: Lab20_RealProblems1_documentSimilarity.pdf

Text Documents: http://library.ucls.uchicago.edu

Posted on April 11th, 2009 by Baker Franke
Filed under: Labs | No Comments »

Program and watch the emergent behavior of Ants!

Assignment Sheet: Lab19_AntBehavior.pdf

There are no starting project files for this one - you can just use an existing GridWorld project to start in.  I suggest something with Critters.  You will want some images, probably.  Here are the ones I used in my simulation:

Ant:

AntHill:

Food:

Posted on April 2nd, 2009 by Baker Franke
Filed under: Labs | No Comments »