1 Data Exploration: The 2016 Summer Olympics

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1 CS 1132 Fall 2016 Assignment 2 due 9/29 at 11:59 pm Adhere to the Code of Academic Integrity. You may discuss background issues and general strategies with others and seek help from course staff, but the implementations that you submit must be your own. In particular, you may discuss general ideas with others but you may not work out the detailed solutions with others. It is never OK for you to see or hear another student s code and it is never OK to copy code from published/internet sources. If you feel that you cannot complete the assignment on you own, seek help from the course staff. When submitting your assignment, follow the instructions summarized in Section 3 of this document. Do not use the break or continue statement in any homework or test in CS Data Exploration: The 2016 Summer Olympics We return to the data from the 2016 Summer Olympics, but this time we give you the full set of data instead of the subset of data for only the medal winning countries. The given data files have been pre-processed only minimally, so you will get to work with a set of data files that is not perfectly simplified a realistic scenario! You need to process the files import data, manipulate, and compute and then answer a set questions and produce a couple visualizations. These answers and visualizations must be achieved programmatically and not hard-coded. I.e., you need to write code to read the data and solve the problems and not pre-determine the answers by personally reading the data files and then hardcoding the answers and graphs. In other words, if we run your functions using a different set of data files that follow the same file format (e.g., data from the Games of a different year), your functions should provide correct answers based on the actual data set used. 1.1 Data files There are three data files, each containing plain text and each has the same number of rows of data; each row contains data for one country. allmedaldata.txt This file contains medal data for all countries that competed, ordered in rows from most medals won to fewest medals won. Columns 1, 2, and 3 store the medal counts for gold, silver, and bronze, respectively. (This is the data file from which the partial medal data of Assignment 1b was obtained.) countries.txt This file lists on each row the name of one country that competed, ordered from most medals won to fewest medals won, i.e., same order as the medals data. Note that a country may just be a grouping for athletes who do not or cannot claim a country. Two such countries in our data are Refugee Olympic Athletes and Independent Olympic Athletes ; we will treat them as countries. athletesbycountry.txt This file lists on each row a country name and the number of competing athletes from that country, e.g., Angola,25. The data in this file is alphabetized by the country names, i.e., the order of the rows is different from the country name data (and medals data) but the set of country names is the same. Take a look at each data file using any text editor, e.g., the Matlab editor (double-click on the filename within the Matlab desktop). If data from another year will be provided, you can expect that they will have the same format as described above: the medals data and country data are ordered from most medals won to fewest medals won, the athletes data is ordered by the alphabetized country names, and the the data files have the same number of rows indicating the number of countries that competed in that year s game. 1

2 1.2 Required, allowed, and forbidden functions You will submit three function files: exactmatches.m and partialmatches.m each contains an independent function, analyzeolympic.m includes the top function analyzeolympic and several subfunctions. The given file splitintwo.m is a completed function that you can download and use Matching strings Implement the following two functions: function idx= exactmatches(c, s) % C is a 1-d cell array of strings. Find all cells in C that match % string s exactly other than case. % idx is a vector of the indices of C where the matches occur. % E.g., if C is { Mat ; uses ; Matlab ; on ; a ; mat } % and s is Mat, then idx is [1 6]. % If there is no match then idx is []. % DO NOT use built-in functions strfind, findstr, or find. function [idx, matches]= partialmatches(c, s) % Find all occurrences of string s in a 1-d cell array C. % C is a 1-d cell array of strings. % s is a string. % idx is a vector of indices of C where s occurs, regardless of case. % matches is a 1-d cell array of the strings in C that match s. % E.g., if C is { Matt ; uses ; Matlab ; on ; a ; mat } % and s is mat, % then idx is [1 3 6] and matches is { Matt Matlab mat } % If s does not occur in C then idx is [] and matches is {}. % DO NOT use built-in functions strfind, findstr, or find. Built-in function strcmp is case-sensitive while strcmpi is case-insensitive. In this assignment we will use case-insensitive comparisons. Be sure to work on and test your functions one at a time! The example in each function comment is a test that you can use; you should create other tests as well. Make effective use of these functions in the remaining parts of the assignment Reading data files Download the file analyzeolympic.m and read carefully the given function headers and specifications and the given code. You already can run this partially implemented function with the following function call: alldata= analyzeolympic( allmedaldata.txt, countries.txt, athletesbycountry.txt ); One line of output should be displayed in the Command Window. From this point on, as you add code, keep running this function to ensure that it remains executable. Now implement the three specified subfunctions by replacing the stubs, i.e., the given dummy code in the subfunctions, with the appropriate code. Do not modify any given function headers. Below is a list of useful functions for implementing the subfunctions countriesformedaldata and combinenumericdata. Use only the built-in functions listed below for handling characters, strings and files. You may not need all of them. You can of course still use general built-in functions not related specifically to strings and files, such as length, zeros, cell, etc. You can use: fopen, fclose, feof, fgetl for file handling, str2double for converting from digits (characters) to a numeric value and strcmpi for comparing strings. 2

3 You must not use built-in functions find, strfind, findstr in this assignment. The document readfile.pdf posted along with this assignment description explains how to use the above functions to read a text file; be sure to read it. There are two other functions that you may find useful: the given function splitintwo for splitting a string into two parts at a delimiting character. Read the function specification and code to learn more. (This is a function that you should be able to write; we provided it only to save you time.) built-in function isempty can be used to determine whether an array (simple or cell array) is empty. E.g., isempty([]) returns 1 (true) while isempty( a ) returns 0 (false). Test each of your implemented subfunctions! Start with just executing analyzeolypmic as shown above. If there s no run-time error, then add some code to print several components of cnames and alldata. Do they look correct? Test some more to confirm your subfunctions correctness and then move on Writing data files You need to implement subfunction dispcountrydata so that it writes the medals and athletes data of specified countries either to the Command Window or to a data file. To do that we need to learn more about function fprintf: outopt= 1; % Output destination: 1 means the screen (Command Window) str1= apple ; str2= pie ; val=pi; fprintf(outopt, %s%10s%6.2f\n, str1, str2, val); If you execute the above code in Matlab you ll see the screen output apple pie 3.14 Did you notice the first argument to fprintf? It s an optional argument for specifying the location to which to print. We haven t used it in the past because all we needed to do was to print to the screen. Now that we want to direct the printing to either the screen or to an output file, we need to use this extra argument: the value 1 sends the printing to the screen; a file identifier obtained by using the fopen command will send the printing to that opened file. The following example code fragment writes a line, same as the example above, to a file named myfile.txt: fid= fopen( myfile.txt, w ); % fid is the file identifier str1= apple ; str2= pie ; val=pi; fprintf(fid, %s%10s%6.2f\n, str1, str2, val); fclose(fid); % Must remember to close the file! The second argument w to the fopen function above specifies that the file is being opened for writing. If the named file already existed in the current folder it would be overwritten; if a file by that name didn t already exist then one would be created. Now add code to the top function analyzeolympic in order to do some testing. For example: dispcountrydata({ Cuba, Russia }, alldata, cnames, 1) Does the above function call print two lines of data to the Command Window, one for Cuba and the other for Russia? Our output looks like this: Cuba 5 gold 2 silver 4 bronze 120 athletes 0.09 medals/athlete Russia 19 gold 18 silver 19 bronze 265 athletes 0.21 medals/athlete We may or may not be showing you the correct medal and athlete values above it s just a demonstration of the neat (nicely lined-up) printing. You should check that your printed values are correct. Next try a non-existent country name instead of Cuba : dispcountrydata({ Disneyland, Russia }, alldata, cnames, 1) Is the print output correct? (One line should say that there s no data for Disneyland and the other line should be the data for Russia.) 3

4 Next test printing to a file: fid= fopen( myfile.txt, w ); dispcountrydata({ Cuba, Russia }, alldata, cnames, fid) Is there a file myfile.txt in your current directory? Is its content correct? Now let s additionally involve function partialmatches in the testing: [idx, namesarray]= partialmatches(cnames, united ); dispcountrydata(namesarray, alldata, cnames, 1) Is the printed output in the Command Window correct? Keep your test code in analyzeolympic as a record of your tests but comment them out once you are satisfied with the testing. 1.3 Answer questions on and make visualizations from the data Add code to analyzeolympic to answer the following questions and make the requested visualizations (draw figures). Your code should print a descriptive answer to the Command Window so that it s clear what question is being answered. Include the question number in the screen output. Observe that question 1 has been answered for you in the provided code as an example. If the question statement says to display the country data then (part of) your answer should be produced by calling the dispcountrydata subfunction. Computation will be required for most of these questions you are not just writing print statements. Except for question 9 below, do not use built-in functions max, min, or sort. You may write additional subfunctions in the file; indeed you are encouraged to use subfunctions to avoid redundancy. 1. How many countries sent athletes to compete? 2. How many medals did North America (Canada, United States, and Mexico) win? Display the total North American medals and the data of the three countries. 3. How did the countries whose names include the word island or islands do? Display their country data. 4. How did the countries whose names include the substring stan do? Display their country data. 5. Which country has the most medals per athlete? (Assume there is only one such country.) Display the country data. 6. Of the countries that sent fewer than 100 athletes, which has the most medals per athlete? (Assume there is only one such country.) Display the country data. 7. Which country won the most gold medals? (Assume there is only one such country.) Display the country data. 8. Which countries, if any, won more gold medals than silver and bronze combined? Display the data of those countries. 9. If the gold, silver, and bronze medals are each worth 3, 2, and 1 points, respectively, which country (or countries) earned the most points? Display the maximum points earned and the associated country data. Youmaylookup andusebuilt-in functionmaxforthis question, but you llget moreprogramming practice if you write your own code to determine the countries that have the max point value. 10. Consider the top three countries who won the most medals; what fraction of all medals did those three countries together take? Display the fraction and the data of the three countries. 11. Write a file MedalWinners.txt that contains the medal and athlete data of all the countries that won at least one medal. Call subfunction dispcountrydata to do this task. No answer needs to be displayed in the Command Window. 12. Draw a bar graph in a figure window showing the number of medals taken by the top 6 medal winning countries. The x-axis should show the country names (unlike the use of country indices in Assignment 1b). Here s a bar graph example: 4

5 xdat= 1:4; ydat=[ ]; bar(xdat, ydat) % 4 bars with heights specified by ydat % The bars are located at x coordinates xdat. The bar graph in Matlab uses numeric axes. If you want to have text labels (country names) on the horizontal axis, then you need to add the following code: barnames= { Name1 Name2 Name3 Name4 }; % cell array containing the bar names set(gca, XTick, xdat, XTickLabel, barnames); % set and gca are built-in functions % XTick and XTickLabel are built-in property names of the graph Be sure to label the x- and y-axes and give your graph a title. Note that if neighboring bar names are long, they may overlap when viewed in the default size figure window. Do not worry about this one can always maximize the figure window when viewing the graph. 13. Look up Matlab documentation on how to draw a pie chart. Then design and draw in a second figure window a meaningful pie chart based on (some part of) the data on medals, countries, and athletes. Have fun! Be sure to label the graph appropriately. 2 Self-check list The following is a list of the minimum necessary criteria that your assignment must meet in order to be considered satisfactory. Failure to satisfy any of these conditions will result in an immediate request to resubmit your assignment. Save yourself and the graders time and effort by going over it before submitting your assignment for the first time. Note that, although all of these are necessary, meeting all of them might still not be sufficient to consider your submission satisfactory. We cannot list everything that could be possibly wrong with any particular assignment! Comment your code! If any of your functions is not properly commented, regarding function purpose and input/output arguments, you will be asked to resubmit. Suppress all unnecessary output by placing semicolons (;) appropriately. At the same time, make sure that all output that your program intentionally produces is formatted in a user-friendly way. Make sure your functions names are exactly the ones we have specified, including case. Check that the number and order of input and output arguments for each of the functions matches exactly the specifications we have given. Test each one of your functions independently, whenever possible, or write short scripts to test them. Check that your scripts do not crash (i.e., end unexpectedly with an error message) or run into infinite loops. Check this by running each script several times in a row. Before each test run, you should type the commands clear all; close all; to delete all variables in the workspace and close all figure windows. 3 Submission instructions 1. Upload files exactmatches.m, partialmatches.m, and analyzeolympic.m to CMS in the submission area corresponding to Assignment 2 before the deadline. 2. When the scores are released, read the grader s feedback carefully. 3. If you need to resubmit, fix all the problems and go back to Step 1! Otherwise you are done with this assignment. Well done! 5