How to use R/Tutorials/Introduction

2006-08-15T18:52:21Z

136.159.197.186: /* Loading and plotting data with R */

'''[[R programming language|R]]''' is both a programming language, and a software environment for statistical computing.

== Loading and plotting data with R ==
This tutorial demonstrates how to plot data loaded from files in R.

* Given the data file ''data.txt'' located at ''<path>'':
1970 45 63
1980 52 59
1990 59 52
2000 63 45

* This data can easilty be loaded into R using the following commands:
setwd("<path>") # change working directory
data <- read.table("data.txt") # load data

* Plotting can then be performed as follows:
# Setup empty plot window
plot(0, type = "n", main = "Plot Title", xlab = "X axis", ylab = "Y axis", xlim = c(1970,2000), ylim = c(0,100))
grid() # add grid
lines(data[,1], data[,2], lty = 1) # draw first dataset
lines(data[,1], data[,3], lty = 2) # draw second dataset
legend("topright", c("first dataset", "second dataset"), lty = c(1, 2) )

* Export of the plot to ''pdf'' is easilty performed by adding ''pdf("filename.pdf")'' prior to the plotting, and ''dev.off()'' after the plotting.
* Export to ''png'' can simmilarly be performed by calling ''png("filename.png")'' prior to the plotting, and ''dev.off()'' after the plotting. ''png("r_plot.png", width = 420, height = 340)'' will, for example yield the following figure:
[[Image:R_plot.png]]

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[[Category:Programming]]

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How to use R/Tutorials/Introduction