Base R
Cheatsheet
Getting Help
Accessing the help files
?mean
Get help of a particularfunction. help.search('weighted mean')
Search the help files for a word or phrase. help(package = 'dplyr')
Find help for a package.
More about an object
str(iris)
Get a summary of an object's structure. class(iris)
Find the class an object belongs to.
Using Packages
install.packages('dplyr')
Download and install a package from CRAN.
library(dplyr)
Load the package into the session, making al its functions available to use.
dplyr::select
Use a particularfunction from a package. data(iris)
Load a built-in dataset into the environment.
Working Directory
getwd()
Find the current working directory (where inputs are found and outputs are sent).
setwd('C://file/path')
Change the current working directory.
Use projects in RStudio to set the working directory to the folder you are working in.
Vectors
Programming
'-1 Creating Vectors		
c(2, 4, 6)	2 4 6	Join elements into a vector
2:6	2 3 4 5 6	An integer sequence
seq(2, 3, by=0.5)	2.0 2.5 3.0	A complex sequence
rep(l:2, times=3)	12 12 12	Repeat a vector
rep(l:2, each=3)	1112 2 2	Repeat elements of a vector
Vector Functions
sort(x)
Return x sorted. table(x)
See counts of values.
rev(x)
Return x reversed. unique(x)
See unique values.
Selecting Vector Elements
By Position x[4] The fourth element.
x[-4] x[2:4] x[-(2:4)] x[c(l, 5)]
x[x == 10] x[x < 0]
All but the fourth.
Elements two to four.
All elements except two to four.
Elements one and five.
By Value
Elements which are equal to 10.
All elements less than zero.
x[x %in% c(l, 2, 5)]
Elements in the set 1, 2, 5.
x['apple']
Named Vectors
Element with name 'apple'.
For Loop
While Loop
for (variable in sequence){ Do something
}
while (conditionH Do something
}
Example
Example
for (i in 1:4){ j <- i + 10 printlj)
}
while (i < 5){ print(i) i <- i + 1
}
If Statements
Functions
if (conditionH
Do something } else {
Do something different
}
function_name <- function(var){ Do something return(new_variable)
Example
if (i > 3){
print('Yes') } else {
print!'No')
}
Example
square <- function(x){ squared <- x*x return(squared)
Reading and Writing Data
Also see the readr package.
Input	Ouput		Description
df <- read.table!'file.txt')	write.table(df,	'file.txt')	Read and write a delimited text file.
			Read and write a comma
df <- read.csv('file.csv')	write.csv(df,	'file.csv')	separated value file. This is a special case of read.table/ write.table.
load('file.RData')	save(df, file =	'file.Rdata')	Read and write an R data file, a file type special for R.
a == b	Are equal	a > b	Greater than	a >= b	Greater than or equal to	is.na{a)	Is missing
a != b	Not equal	a < b	Less than	a <= b	Less than or equal to	is.null(a)	Is null
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Types
Converting between common data types in R. Can always go from a higher value in the table to a lower value.
as.logical
as.numeric
as.character
as.factor
TRUE, FALSE, TRUE
'ľ, '0
levels:
Boolean values (TRUE or FALSE).
Integers or floating point numbers.
Character strings. Generally preferred to factors.
Character strings with preset levels. Needed for some statistical models.
Maths Functions
log(x) exp(x) max(x) min(x)
rouncKx, n)
signif(x, n)
cor(x, y)
Natural log. Exponential. Largest element. Smallest element.
sum(x) mean(x) median(x) quantile(x)
Round to n decimal rank(x) places.
Round to n significant figu res.
Correlation.
sd(x)
Sum.
Mean.
Median.
Percentage quantiles.
Rankof elements.
The variance.
The standard deviation.
Variable Assignment
> a <- 'apple'
> a
[1] 'apple'
The Environment
ls()
rm(x)
rmdist = IsO)
List all variables in the environment.
Remove x from the environment.
Remove all variables from the environment.
You can use the environment panel in RStudio to browse variables in your environment.
Matrices
m <- matrix(x, nrow = 3, ncol = 3)
Create a matrix from x.
j  m[2, ] - Select a row
■
m [ , 1] - Select a column
I m[2, 3] - Select an element
Lists
t(m)
Transpose m %*% n Matrix Multiplication solve(m, n)
Find x in: m * x = n
I <- list(x = 1:5, y = c( 'a', 'b'))
A list is a collection of elements which can be of different types.
l[[2]]
Second element of 1.
Also see the dplyr package.
Ul]
New list with
l$x
l['y']
New list with
Element named only the first only element
element. ' named y.
Data Frames
df <- data.frame(x = 1:3, y = c('a', 'b', 'c'))
A special case of a list where all elements are the same length.
List subsetting df$x df[[2]] J
2	b		Understanding a data frame	
			Viewldf)	Seethe full data
3	c			frame.
Matrix subsetting			headldf)	See the first 6
				'OWS.
df[ , 2]
df[2, ]
df[2, 2]
nrow(df)
Number of rows. |
ncoKdf)
Number of columns.
dim(df)
Number of columns and rows.
cbind
iind columns.
rbind - Bind rows.
Strings
pastelx, y, Sep = ' paste(x, collapse = grep(pattern, x)
Also see the stringr package.
)      Join multiple vectors together. ' )    Join elements of a vector together. Find regular expression matches in x.
gsub(pattern,   replace, x)   Replace matches in x with a string. toupper(x) Convertto uppercase.
tolower(x) Convertto lowercase.
nchar(x) Number of characters in a string.
Factors
factor(x)
Turn a vector into a factor. Can set the levels of the factor and the order.
cut(x, breaks = 4)
Turn a numeric vector into a factor by 'cutting' into sections.
Statistics
lm(y ~ x, data=df)
Linear model.
glm(y ~ x, data=df)
Generalised linear model.
summary
Get more detailed information out a model.
t.test(x, y)
Perform a t-testfor difference between means.
pairwise.t.test
Perform a t-test for paired data.
prop.test
Test fo r a difference between proportions.
aov
Analysis of va riance.
Distributions
	Random Variates	Density Function	Cumulative Distribution	Quantile
Normal	rnorm	dnorm	pnorm	qnorm
Poisson	rpois	dpois	ppois	qpois
Binomial	rbinom	dbinom	pbinom	qbinom
Uniform	runif	dunif	punif	qunif
Also see the ggplot2 package.
plot(x)
Values of x in order.
Dates
plot(x, y)
Values of x against y.
hist(x)
Histogram of
See the lubridate package.
RStudio® is a trademark of RStudio, Inc. • CC BY Mhairi McNeill • mhairihmcneill@gmail.com • 844-448-1212 ■ rstudio.com
Learn more at web page orvignette • package version • Updated: 3/15