basic-session-code.R

#----------------------------------------------------------------------------------------------
# File: basic-session-code.R
# Date: 03-04-2012
# Author: Eric Nantz
# URL: https://github.com/thercast/basic-interaction-with-R/blob/master/basic-session-code.R
# Email: theRcast@gmail.com
# Purpose: Example of a basic R session demonstrated in the R-Podcast episode 3
#          www.r-podcast.org/the-r-podcast-episode-3-basic-interaction-with-r
# License: Creative Commons Attribution-ShareAlike 3.0 Unported License
#----------------------------------------------------------------------------------------------

# Try entering the following commands in the R Console one line at a time
2+3
pi*(6^2)

# a numeric vector can be created using the c() function
# for example, six high school GPA scores:

c(3.67, 3.95, 2.89, 4.00, 3.83, 3.18)

# Using assignment sequence <- or = to assign this vector to an object called x
x <- c(3.67, 3.95, 2.89, 4.00, 3.83, 3.18)
x = c(3.67, 3.95, 2.89, 4.00, 3.83, 3.18)
x

# access certain elements of the vector using [n] where n is index of desired element
x[1]

# count the number of elements in x using the length() function
length(x)

# compute the mean using the mean() function
mean(x)

# access the help page for mean to see if a trimmed mean can be computed
# the following commands are equivalent
help(mean)
?mean

# many functions have examples that can be run by using the example function
example(mean)

# use the trim argument to get a trimmed mean
mean(x, trim=1/6)

# equivalent to the following
x.sorted <- sort(x)
x.trimmed <- x.sorted[c(-1,-6)]
mean(x.trimmed)

# other statistics can be calculated using the summary function
summary(x)

# a simple scatterplot can be generated by the plot function
plot(x)

# to install packages from command line, use install.packages function
install.packages("ggplot2")

# to load a package from command line, use the library function
library(ggplot2)

# to save workspace from command line, use the save.image or save function
save.image(file="myWorkspaceAll.RData")
save(x, file="myWorkspaceSubset.RData")

# to quit R, use q()
q()