MathWit entry/demo course - Math0

First, download R here if you are using windows OS:

http://cran.r-project.org/bin/windows/base/

For Ipad:  https://apps.apple.com/ca/app/r-programming-compiler/id1158038782?platform=ipad

R can be installed under Windows 7 or Windows 8. Users who use our tutorial services can get help on R installation and some post-installation issues. 

Here is an example of creating your first data matrix, with two rows and ten columns. The i-j position is simply the summation of the two indices. 

> sample_data<-matrix(nrow=2,ncol=10) > c_col<-c('A','B','C','D','E','F','G','H','I','J') > c_row<-c('Program A','Program B') > colnames(sample_data)<-paste(c_col) > rownames(sample_data)<-paste(c_row) > for(j in 1:10){ + for(i in 1:2){ + sample_data[i,j] = i+j + } + } > sample_data A B C D E F G H I J Program A 2 3 4 5 6 7 8 9 10 11 Program B 3 4 5 6 7 8 9 10 11 12

If you wish to see only the line by line code, you can copy and paste the following, either line by line or all together:

sample_data<-matrix(nrow=2,ncol=10) c_col<-c('A','B','C','D','E','F','G','H','I','J') c_row<-c('Program A','Program B') colnames(sample_data)<-paste(c_col) rownames(sample_data)<-paste(c_row) for(j in 1:10){ for(i in 1:2){ sample_data[i,j] = i+j } } sample_data

Your output will be looks like:

> sample_data
                 A  B  C  D  E  F   G   H   I    J
Program A 2   3  4   5  6   7   8    9  10  11
Program B 3   4  5   6  7   8   9   10  11 12

Next, we can modify some entries. You can just run the following code and observe the result:

> sample_data[1,]<-c(19, 12, 3, 22, 11, 9, 16, 20, 8, 14) > sample_data A B C D E F G H I J Program A 19 12 3 22 11 9 16 20 8 14 Program B 3 4 5 6 7 8 9 10 11 12 > sample_data[2,1]<- 17 > sample_data A B C D E F G H I J Program A 19 12 3 22 11 9 16 20 8 14 Program B 17 4 5 6 7 8 9 10 11 12