R Cheat Sheet | A Guide of R Glossary

Operator

Purpose

<- or  =

Assignment

#

Comment

/

Division

<<-

Global Assignment

%%

Remainder

*

Scalar Multiplication

%/%

Integer Division

%*%

Matrix Multiplication

v[1]

First vector element

Function Name

Purpose

help.start()

opens help

class(df_name)

Returns class of the given object

?tidyverse

Shows tidyverse package documentation

str(df_name)

Returns information and structure of the given object

?function_name

Shows in-built functions’ documentation

??”some_input”

Shows a given input’s documentation

Method/Definition

Description

summary(df_name)

Returns the statistics of data in a descriptive format

view(df_name)

Opens the editor

df_name = data.f­ram­e(s­tudent­ID=­1:5­, year=c­("1960",­"­1980","1990­"­,"1998",­"­2001"),­sco­re=­c(6,1,­3,2,2))

Dataframe definition

Method

Purpose

order(index) 

To find the index to sort a vector

apply(data, axis, function_name)

To apply data to function in the particular axis

data = read.csv(file.choose())

To read data from the file explorer

dim()

To find dimensions of matrix/dataframe/vector

lapply(data, function_name)

To apply the data to the function

getwd()

Gets the working directory

length()

To find the vector length

install.packages(“package_name”)

Installs the required R package

names()

Returns the column names

setwd(“C:/file/path”)

To set the current working directory

rapply(data, function_name, how)

Depending on the value of how, the data is applied to the function

sort()

To sort a vector

rm(variable_name)

To remove the variable

detach(“package name”)

Detaches the given package

ls()

To list all the variables

library(“package name”)

Makes contents of the given package ready to use

Method

Purpose

range(vec)

To find the range of a vector

num = c(3,7,­2,1­,8,5)

Defining a numeric vector

rep(1:­8, t­imes=2)

Replicates the elements of the vector by the given number of times

sd(vec)

To find the standard deviation of a vector

chr = c("rte",­"­qhz ­")

Defining a character vector

var(vec)

To find the variance of a vector

log = c(FALSE­, ­FALSE, TRUE)

Logical vector

whi­ch.m­ax­(vec)

To find the position of the max value

which.m­in­(ve­c)

To find the position of the min value

mean(vec)

To find the mean of the values of a vector

Method

Purpose

rbind(­mat­rix1,matrix2)

To row bind matrix1 and matrix2

cbind(­matrix­1,matrix2)

To column bind matrix1 and matrix2

mat = matrix­(1:15, nrow=3, ncol=5)

To define a matrix

1D = array(­1:14)

To define a 1-dimens­ional array

2D = array(­1:20, dim = c(1,3))

To define a 2-dimens­ional array

3D = array(­1:20, dim = c(1,4,5))

To define a 3-dimens­ional array

Method

Purpose

aov()

To find ANOVA or Analysis of Variance

wilcox.te­st(­data)

To find the Wilcox test on the given data

t.test­(data)

To find 1 sample t-test of the given data

cor.te­st(­dat­a1,­data2)

To find the correl­ation test of the given data

t.test­(da­ta1­,data2)

To find the 2 sample t-test of the given data

chisq.t­es­t(data)

To find the Chi-square test of the given data

t.test­(pr­e, p­ost­, pa­ire­d=TRUE)

To find the paired sample t-test of the given data

shapir­o.t­est­(data)

To find the Shapiro test of the given data

Method

Purpose

colSum­s(d­ata[])

To find the column sum of a particular column of the given data

rowSum­s(d­ata[])

To find the row sum of a particular row of the given data

summar­y(lm(y ~ x1 + x2 + x3, data=m­ydata))

To find the multiple regression of a given data

cluster = kmeans­(data)

To find the kmeans cluster analysis of a given data

summar­y(glm(y ~ x1 + x2 + x3, family­="", data=m­ydata))

To find the classi­fic­ation of a given data

colMea­ns(­data[])

To find the column mean of a particular column of the given data

rowMea­ns(­data[])

To find the row mean of a particular row of the given data

Method

Purpose

geom_hist()

To find the histogram of a given data

coord_­flip()

To flip the x and y coordi­nates of a given point

ggplot­(data = NULL, mapping = aes(), ...)

To initia­lize a ggplot object of a given data

geom_d­ensity()

To produce a density plot of a given data

facet_­grid()

To lay out panels in a grid of a given data

geom_point()

To produce scatter plots of a given data

qplot(­data, line=T­RUE­,...)

To produce the quantile plot of a given data

geom_bar()

To produce a bar graph of a given data

Method

Purpose

paste (…, sep = " ", collapse = NULL)

Concat­enate the vectors after converting to character

to­lower()

Converts the given text to ­lower case characters

toupper()

Converts the given text to ­upper case characters

toStri­ng(x)

A helper function to produce a single character string

substr­ing­(ch­r, n, n)

To replace or retrieve the substring of a given string

Method

Purpose

rexp(n)

To find the Expone­ntial distri­bution of n

runif(n, min = 0, max = 1)

To find the Uniform distri­bution of n

rbinom(n, size, prob)

To find the Binomial distri­bution of n

rnorm(­n, m­ean, sd)

To find the Normal distri­bution of n

rpois(­n, size)

To find the Poisson distri­bution of n

Statement

Purpose

if(condi­tion){ block of statements } else { block of statements }

if-else statements format

while(condi­tion){ block of statements }

while loop format

for(variable in the sequence){ block of statements }

for loop format