% File -> Import Data 
% Number of header rows = 1

% format numbers; by default: decimals
format short g

% sort data and return index of sort
[dataSorted,sortIndex]=sortrows(data,[5 1 4]);

% first row of textdata is garbage
textdata2=textdata(2:size(textdata,1),:);
% apply sort index to textdata
textdataSorted=textdata2(sortIndex,:);

% read geography info into vectors, which will act as lookup tables
[geoCode,geoName]=textread('geography.csv','%q %q',-1,'delimiter',',');
geoCode=geoCode(2:length(geoCode));
geoName=geoName(2:length(geoName));

% extract data related to NY, the region of New York State
[dataNY,textdataNY]=extractRegion(dataSorted,textdataSorted,'NY');
[dataTX,textdataTX]=extractRegion(dataSorted,textdataSorted,'TX');

yearMin = min(data(:,5));

dataNYTime = ((dataNY(:,5) - yearMin) * 52) + (dataNY(:,1) * 4) + dataNY(:,4);
dataTXTime = ((dataTX(:,5) - yearMin) * 52) + (dataTX(:,1) * 4) + dataNY(:,4);

plot(dataNYTime, dataNY(:,2),'b'), xlabel('Time'), ylabel('Price in cents/gallon'), title('Gasoline prices in New York versus Texas');
hold on;
plot(dataTXTime, dataTX(:,2),'r')
hold off;
legend('New York', 'Texas');