# This document is from Stat 135, Spring 07
# It covers some basic R features inclding:
# Vectors, Assignments, extraction, and getting help
# You can make comments like this
# Equality means assigning the thing on the right to the left
a = 3
# Alternatively, one can use an arrow
a <- 3
6 -> b
# Just don't do this
3 = a
# There are several data structures, we first consider vectors
scoresM = c(5,8,3,5,2)
vec = 1:5
scores
vec
# or all at once
scores; vec
# note that R can be used as a calculator
2^4 - 1
# Most functions that operate on scalars operate
# pointwise on vectors
(1:10)^2; exp( scoresM ); 1:10 + 1:10
a+b
ls() # see what is in your workspace
rm(a) # remove an object
a+b # doesn't work because you removed a
# you can paste things together and extract from them
vec1 = 1:10
vec2 = c(3,7,14)
vec3 = c( vec1, vec2 )
vec3
vec3[12]
vec3[7:12]
vec3[-(7:12)]
# we can generate a vector of random numbers
data = rnorm(10^4)
data
hist(data)
################### HOW TO GET HELP ###################
?rnorm
help(rnorm)
# both are the same, you can also enter up top
# If you aren't using a GUI, then open the
# browser and go to search engine and keywords
help.start()
# note how there are default values
rnorm(10,50)
# 10 normals with mean 50 and variance 1
########################################################
# someone tells you about the function hist
hist(data)
# someone tells you about the function truehist
truehist(data)
# But you get an error
?truehist
# then try
help.search('truehist')
#the indication is that MASS needs to be added
library(MASS)
truehist(data)