Data Structures In R

Data structures is used to identify and represent the data..

There are different types of data structures in R such as

1) vector:It is homogeneous(same) type and having one dimension.

2) list:It is heterogeneous(different) type and having one dimension..

3)matrix :It is homogeneous type and having 2 dimensions..

4)data frame:It is heterogeneous type and having 2 dimensions..

5) factors:It is homogeneous type and having one dimension..

6)Arrays:It is homogeneous type and having n number of dimensions..

1)vectors: one dimensional arrays are vectors,homogeneous

syntax:

variable name<-c()

Example:

a<-c(24,56,78)

a

b<-c("one","two","three")

b

x<-c(TRUE,FALSE,TRUE,FALSE)

x

y<-10   #element vector(scalars)

Where a,b,x is the variable name and c is used for combine the value..

Accessing vector elements

vec<-c("a","d","w","e","g")

vec

vec[3]  #output:[1] "w"

vec[c(2,5)]  #ouput: [1] "d" "g"

2)Matrix:These are two dimensions data structures 

mat<-matrix(c(1,2,3,4),nrow=2,ncol=2)  #by default column wise

mat

ouput: 1  3

            2  4

mat1<-matrix(c(1,2,3,4),nrow=2,ncol=2,byrow=TRUE) # if true matrix filed by rows

mat1

ouput: 1  2

            3 4

Note:

Compare both the output to know the result

Accessing matrix elements

mat<-matrix(c(1,2,3,4),nrow=2,ncol=2) 

or

mat<-matrix(c(1:4),nrow=2,ncol=2)

mat[1,]  #returns 1st  row in matrix

mat[,1]  #returns 1st column in matrix

mat[1,2] #returns the elements in the first row of second column

Arrays:are multidimensional..

#dim=c(row,column,number of matrix)

x1<-array(1:12,dim=c(2,2,3)) 

x1

Access elements in  in arrays

#print 2 rows of 2 matrix

print(x1[2,,2])

#print 2 column of 3 matrix

print(x1[,2,3])

#print all column and rows of 3 matrix

print(x1[,,3])

Note:

Basic data types in R are character, numeric, integer, complex, and logical.

Objects may have attributes, such as name, dimension, and class.