Assigning operator

It will store a value in a variable.

a<-2
a

## [1] 2

R Markdown cheat sheet

Functions

R functions are invoked by its name

c(1,2,3)

## [1] 1 2 3

Comments

1 + 1 # this is a comment

## [1] 2

Install Packages

Tools –> Install Packages —> Select Package name

ctrl+Alt+I iNSERT CHUNCK
cTRL+R for executing the chunk

x<-c(1:20)
x

##  [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20

>install.packages("ggplot2")

How TO CALL Library

library(datasets)

help function

help(c)

## starting httpd help server ... done

arguments

x<-c(1,2,3,5:10,NA)
help(sd)
args(sd)

## function (x, na.rm = FALSE) 
## NULL

sd(x)

## [1] NA

sd(x,na.rm = TRUE)

## [1] 3.162278

sd(x,TRUE)

## [1] 3.162278

sd(TRUE,x)

## Warning in if (na.rm) "na.or.complete" else "everything": the condition has
## length > 1 and only the first element will be used

## [1] NA

sd(na.rm = TRUE,x)

## [1] 3.162278

sd(TRUE,x=x)

## [1] 3.162278

Places to post queries

r-help@r-project.org github statckoverflow

Datacamp

try r

codeschool

Assignment

Create one 5 dimensional vector of values 4,7,3,2,5 as ‘x’

x<-c(4,7,3,2,5)
x

## [1] 4 7 3 2 5

Add 2 with x and assign the value to y

y<-x+2
y

## [1] 6 9 5 4 7

Find the mean , sd of y

mean(y)

## [1] 6.2

sd(y)

## [1] 1.923538

Create another variable Z as combinational of 2,3

z<-c(2,3)

Add x and z

x + z

## Warning in x + z: longer object length is not a multiple of shorter object
## length

## [1]  6 10  5  5  7

Datacamp

try r

R has basic or atomic classes of objects:

character numeric integer complex logical

x<-1
class(x)

## [1] "numeric"

x<-1L
class(x)

## [1] "integer"

?class

Attributes

names ,dimnames dimensions class length

x<-c(1:20)
length(x)

## [1] 20

x<-c(1:20,"shyama")
length(x)

## [1] 21

##  [1] "1"      "2"      "3"      "4"      "5"      "6"      "7"     
##  [8] "8"      "9"      "10"     "11"     "12"     "13"     "14"    
## [15] "15"     "16"     "17"     "18"     "19"     "20"     "shyama"

x<-c(1:20)
x<-as.character(x)
class(x)

## [1] "character"

x<-c(1:20)
x<-as.factor(x)
class(x)

## [1] "factor"

Entering Input

x<-1
print(x) #explicit printing

## [1] 1

Creating vectors

c()function can be used to create vectors of objects

x<- c(0.5, 0.6)    #NUMERIC
x<- c(TRUE, FALSE)  #logical
x<- c(T,F)  #logical
x<- c("a","b","c")

Mixing objects

c(TRUE,2)

## [1] 1 2

c(TRUE,2,FALSE,"shyama")

## [1] "TRUE"   "2"      "FALSE"  "shyama"

x<-1:6.0
class(x)

## [1] "integer"

as.numeric(x)

## [1] 1 2 3 4 5 6

x<-c(1,2,3)
class(x)

## [1] "numeric"

x<-c("a","b","c")
class(x)

## [1] "character"

as.numeric(x)

## Warning: NAs introduced by coercion

## [1] NA NA NA

matrix

matrix(1:20,nrow = 2)

##      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
## [1,]    1    3    5    7    9   11   13   15   17    19
## [2,]    2    4    6    8   10   12   14   16   18    20

args(matrix)

## function (data = NA, nrow = 1, ncol = 1, byrow = FALSE, dimnames = NULL) 
## NULL

matrix(1:20,nrow = 2,byrow = TRUE)

##      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
## [1,]    1    2    3    4    5    6    7    8    9    10
## [2,]   11   12   13   14   15   16   17   18   19    20

?dim
x<-1:10
dim(x)<-c(2,5)
x

##      [,1] [,2] [,3] [,4] [,5]
## [1,]    1    3    5    7    9
## [2,]    2    4    6    8   10

y<-20:30
x<-1:10
y<-20:29
z<-50:59
x

##  [1]  1  2  3  4  5  6  7  8  9 10

##  [1] 20 21 22 23 24 25 26 27 28 29

##  [1] 50 51 52 53 54 55 56 57 58 59

cbind(x,y)

##        x  y
##  [1,]  1 20
##  [2,]  2 21
##  [3,]  3 22
##  [4,]  4 23
##  [5,]  5 24
##  [6,]  6 25
##  [7,]  7 26
##  [8,]  8 27
##  [9,]  9 28
## [10,] 10 29

rbind(x,y,z)

##   [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
## x    1    2    3    4    5    6    7    8    9    10
## y   20   21   22   23   24   25   26   27   28    29
## z   50   51   52   53   54   55   56   57   58    59

x<-c(1,3,5)
y<-c(2,3,4,5)
x

## [1] 1 3 5

## [1] 2 3 4 5

cbind(x,y)

## Warning in cbind(x, y): number of rows of result is not a multiple of
## vector length (arg 1)

##      x y
## [1,] 1 2
## [2,] 3 3
## [3,] 5 4
## [4,] 1 5

List

x<-list(c(1,2,3),c("shyama","manasa"))
x

## [[1]]
## [1] 1 2 3
## 
## [[2]]
## [1] "shyama" "manasa"

x[1]

## [[1]]
## [1] 1 2 3

x[2]

## [[1]]
## [1] "shyama" "manasa"

x[1][2]

## [[1]]
## NULL

x[[c(1,2)]]

## [1] 2

x[[c(1,2)]]

## [1] 2

x[[c(2,1)]]

## [1] "shyama"

Factors

x<-factor(c("yes","yes","no","yes"))
x

## [1] yes yes no  yes
## Levels: no yes

class(x)

## [1] "factor"

x<-factor(c("yes","yes","no","yes"))
class(x)

## [1] "factor"

x<-factor(x)
class(x)

## [1] "factor"

## [1] yes yes no  yes
## Levels: no yes

args(factor)

## function (x = character(), levels, labels = levels, exclude = NA, 
##     ordered = is.ordered(x), nmax = NA) 
## NULL

table

table(y)

## y
## 2 3 4 5 
## 1 1 1 1

## [1] 2 3 4 5

Create a list whose first element is 2- element set of names say “Rekha” and “shyama”,second element is a set of numbers like 2,3,5,19,2,7,5,5

x<-list(c("Rekha","shyama"),c(2,3,5,19,2,7,5,5))
x

## [[1]]
## [1] "Rekha"  "shyama"
## 
## [[2]]
## [1]  2  3  5 19  2  7  5  5

check the class of second element of the list

class(x[[2]])

## [1] "numeric"

print the 4th element of the 2nd element of the list

x[[c(2,4)]]

## [1] 19

## [[1]]
## [1] "Rekha"  "shyama"
## 
## [[2]]
## [1]  2  3  5 19  2  7  5  5

change the 1st element of the list as factor

y<-as.factor(x[[1]])
y

## [1] Rekha  shyama
## Levels: Rekha shyama

Find out the frequency of each element of the 2nd element of the list

table(x[[2]])

## 
##  2  3  5  7 19 
##  2  1  3  1  1

## [[1]]
## [1] "Rekha"  "shyama"
## 
## [[2]]
## [1]  2  3  5 19  2  7  5  5

Missing value

is.na() #either there is na or not is.nan() #either there is nan or not NA NaN

x<-c(1,2,3,NA,1,NaN)
x

## [1]   1   2   3  NA   1 NaN

is.na(x)

## [1] FALSE FALSE FALSE  TRUE FALSE  TRUE

is.nan(x)

## [1] FALSE FALSE FALSE FALSE FALSE  TRUE

x<-c(1,2,NaN,NA,4)
is.na(x)

## [1] FALSE FALSE  TRUE  TRUE FALSE

is.nan(x)

## [1] FALSE FALSE  TRUE FALSE FALSE

Data Frames

set of frames is Data frames Length of the vertical frames is equal to length of rows

to import excel sheets in to R use read.table

to import excel sheets to csv use read.csv

args(data.frame)

## function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, 
##     stringsAsFactors = default.stringsAsFactors()) 
## NULL

x<-data.frame(name=c("shyama","rekha","Athanu","sujith"),age=c(24,23,23,24),sex=c("F","F","M","M"))
x

##     name age sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

class(x)

## [1] "data.frame"

y<-cbind(name=c("shyama","rekha","Athanu","sujith"),age=c(24,23,23,24),sex=c("F","F","M","M"))
y

##      name     age  sex
## [1,] "shyama" "24" "F"
## [2,] "rekha"  "23" "F"
## [3,] "Athanu" "23" "M"
## [4,] "sujith" "24" "M"

class(y)

## [1] "matrix"

z=as.data.frame(y)
z

##     name age sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

class(z)

## [1] "data.frame"

##     name age sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

str(x)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: Factor w/ 4 levels "Athanu","rekha",..: 3 2 1 4
##  $ age : num  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

coordinates of each observation

x[,2]

## [1] 24 23 23 24

x[2,2]

## [1] 23

x[2,]

##    name age sex
## 2 rekha  23   F

names(x[,2])

## NULL

as.character(x[,1])

## [1] "shyama" "rekha"  "Athanu" "sujith"

class(as.character(x[,1]))

## [1] "character"

str(x)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: Factor w/ 4 levels "Athanu","rekha",..: 3 2 1 4
##  $ age : num  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

x[,1]=as.character(x[,1])
str(x)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: chr  "shyama" "rekha" "Athanu" "sujith"
##  $ age : num  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

x[,2]=as.integer(x[,2])
str(x)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: chr  "shyama" "rekha" "Athanu" "sujith"
##  $ age : int  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

##      name     age  sex
## [1,] "shyama" "24" "F"
## [2,] "rekha"  "23" "F"
## [3,] "Athanu" "23" "M"
## [4,] "sujith" "24" "M"

class(y)

## [1] "matrix"

y=as.data.frame(y)
str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: Factor w/ 4 levels "Athanu","rekha",..: 3 2 1 4
##  $ age : Factor w/ 2 levels "23","24": 2 1 1 2
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

##     name age sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

y[,2]=as.integer(as.character(y[,2]))
str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: Factor w/ 4 levels "Athanu","rekha",..: 3 2 1 4
##  $ age : int  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

y[,1]=as.character(y[,1])
str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: chr  "shyama" "rekha" "Athanu" "sujith"
##  $ age : int  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

y$age

## [1] 24 23 23 24

str(y$age)

##  int [1:4] 24 23 23 24

str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ name: chr  "shyama" "rekha" "Athanu" "sujith"
##  $ age : int  24 23 23 24
##  $ sex : Factor w/ 2 levels "F","M": 1 1 2 2

str(y$name)

##  chr [1:4] "shyama" "rekha" "Athanu" "sujith"

##     name age sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

names(y)

## [1] "name" "age"  "sex"

nrow(y)  ## no of rows

## [1] 4

ncol(y)  ##no of cols

## [1] 3

y<-data.frame(c("shyama","rekha","Athanu","sujith"),age=c(24,23,23,24),sex=c("F","F","M","M"))
y

##   c..shyama....rekha....Athanu....sujith.. age sex
## 1                                   shyama  24   F
## 2                                    rekha  23   F
## 3                                   Athanu  23   M
## 4                                   sujith  24   M

class(y)

## [1] "data.frame"

colnames(y)<-c("Name","Age","Sex") ##to change the attribute names
y

##     Name Age Sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ Name: Factor w/ 4 levels "Athanu","rekha",..: 3 2 1 4
##  $ Age : num  24 23 23 24
##  $ Sex : Factor w/ 2 levels "F","M": 1 1 2 2

y[,1]<-as.character(y[,1])
y

##     Name Age Sex
## 1 shyama  24   F
## 2  rekha  23   F
## 3 Athanu  23   M
## 4 sujith  24   M

str(y)

## 'data.frame':    4 obs. of  3 variables:
##  $ Name: chr  "shyama" "rekha" "Athanu" "sujith"
##  $ Age : num  24 23 23 24
##  $ Sex : Factor w/ 2 levels "F","M": 1 1 2 2

MyFirstClass

Shyama

September 29, 2015

Assigning operator

R Markdown cheat sheet

Functions

Comments

Install Packages

How TO CALL Library

help function

arguments

Places to post queries

Datacamp

try r

codeschool

Assignment

Create one 5 dimensional vector of values 4,7,3,2,5 as ‘x’

Add 2 with x and assign the value to y

Find the mean , sd of y

Create another variable Z as combinational of 2,3

Add x and z

Datacamp

try r

R has basic or atomic classes of objects:

Attributes

Entering Input

Creating vectors

Mixing objects

matrix

List

Factors

table

Create a list whose first element is 2- element set of names say “Rekha” and “shyama”,second element is a set of numbers like 2,3,5,19,2,7,5,5

check the class of second element of the list

print the 4th element of the 2nd element of the list

change the 1st element of the list as factor

Find out the frequency of each element of the 2nd element of the list

Missing value

Data Frames

to import excel sheets in to R use read.table

to import excel sheets to csv use read.csv

coordinates of each observation