Vectors in R

    A vector is a collection of elements with the same type. A vector can be created by c() function or any other sequence generating commands. Vectors are widely used data types in R. In this post, we'll briefly learn some of the methods with vectors in R.
   There is a list type of objects in R and the main difference between vector and list is vector collects only certain types of elements like numeric, character, double. Lists can hold any type of elements together.


Generating vectors

> v=c(1,1,2,3,5)
> v
[1] 1 1 2 3 5

> c("apple", "banana", "melon", "orange") 
[1] "apple"  "banana" "melon"  "orange"

We can generate integer elements with sequence generation functions.

> seq.int(1,10)    #  
 [1]  1  2  3  4  5  6  7  8  9 10 

Random data can also be collected into the vectors.

> runif(5)        
[1] 0.81286610 0.29486167 0.03254023 0.31721261 0.93284194

 
Creating time series vectors.

> seq.Date(from=Sys.Date(), to=Sys.Date()+5,by="day")   
[1] "2016-11-24" "2016-11-25" "2016-11-26" "2016-11-27" "2016-11-28" "2016-11-29"

To assign the vector into the variable.

> assign("vv", c(22,12,23))
> vv
[1] 22 12 23

Each element has an index in a vector and we can get the element through its index.

> a=seq.int(20,11)
> a
[1] 20 19 18 17 16 15 14 13 12 11

> a[3]
[1] 18

The 'length' command shows the length of the vector.

> v=seq(-5,5)
> length(v)
[1] 11
> v
 [1] -5 -4 -3 -2 -1  0  1  2  3  4  5

The 'typeof' command shows the type of vector.

> m=runif(5)
> typeof(m)
[1] "double"
> m=seq.int(10)
> typeof(m)
[1] "integer"
> m=c("dog","cat")
> typeof(m)
[1] "character"

 
To create a vector from input data, we can use the 'scan' command. 

> m=scan()　　　
1: 5
2: 34
3: 45
4:
Read 3 items
> m
[1]  5 34 45
> 

Some other operations with vectors.

> b=c(3,43,12,29)
> sort(b)                 # sorts vectors elements
[1]  3 12 29 43
> rev(b)                  # provides reverse order
[1] 29 12 43  3
> sum(b)                  # sums up vector
[1] 87
> mean(b)                 # shows mean value
[1] 21.75
> which(b>20)          # shows element id higher than 20
[1] 2 4
> b[which(b>20)]       # shows elements higher than 20
[1] 43 29
> b[b>20]              # shows elements higher than 20
[1] 43 29
>

> d=c(20,21,23)                               

> e=c(1,2)

> append(d, e)       # appends two vector elements 

[1] 20 21 23 1 2
>

In this tutorial, we've briefly learned about vectors in R.