R is a statistics program. I can calculate statistical functions and draw nice graphs. Today I used it for showing some graphs.

I use R on my linux system, but it also works on Windows. To install it look at website of R.

Data from a file can be read with the function read.table(filename), where filename is the name of filename that you want to read. This would look like:

visitors <- read.table('visitors.dat')

The visitors.dat should contains two columns like this:

id  visitors
1    100
2    204
3    70
4    79
5    99
6    100
...  ...

You can also use the read.csv(filename) function. This will read comma separated values files.

When the file is read, the data will be put in a table named visitors, because of the variable and the <- operator. Typing visitors on the R prompt will show the contents of the table. To plot the data, type plot(visitors). It’s that easy. Plot will choose a way to show the data.

After plot you can type lines(visitors) to add the lines to connect the dots.

It’s also possible to add a line to show to the trend in the data:

lines(lowess(visitors), col='green')

Which will add a green line to the plot, showing the trend.

That’s it. Please don’t ask me questions about statistics, because I have no idea at the moment. I want to know more about it and will find some books and information.

The R program can do much, this is just the beginning of the possibilities. Of course there are many uses for statistics, like performance of your program.