## R Basics

October 7, 2009by Jeremy Koelmel (jpk07)

R basics

October 7, 2009

by Jeremy Koelmel (jpk07)

R Basics, Here is how to:

1) to manually set up data in R

2) Import data from outside R (as .txt)

3) export data out of R (as .txt)

4) To export and import R code to run in R

# writing simple exponential data in R

#assign arrays

X <- c(1:10);

Y <- c(X^2);

#matrix

XYdata <- cbind(X,Y);

#transpose data

XYdata <- t(XYdata);

#select one

XYdata[,7];

# Plot

plot(X, Y, main=”Exponential Function”);

#exporting

write.table(XYdata, file=”Desktop/XYdata.txt”, sep=”,”);

#getting the working directory

getwd();

#setting the working directory

setwd(”~/Desktop”);

#Importing

RoseData <- read.table(file=”RoseData.txt”);

#see all plots

plot(RoseData, main=”Multiflora Rose Distribution in a Pine Stand”);

#comparing two variables

MFRdensity <- RoseData[,3];

DistanceFromEdge <- RoseData[,9];

plot(DistanceFromEdge,MFRdensity);

#lm(DistanceFromEdge,MFRdensity); not working because more than one instance of y for single x

# Writing .R function: Write in a simple text format (.txt) and Save as “blahblah”.R

# ie. in this format

X <- c(1:10);

Y <- c(X^2);

XYdata <- cbind(X,Y);

plot(X, Y, main=”Exponential Function”);

# get to the right directory

setwd(”Dir”);

# enact it in R

source(”Graph.R”);

Love Jeremy

PS: Further Resources:

http://www.math.ilstu.edu/dhkim/Rstuff/Rtutor.html

http://www.cyclismo.org/tutorial/R/