R language vector

Vectors are the most basic R language data objects, with six types of atomic vectors. T hey are logical, integer, double, complex, character, and original.

Create a vector

Single-element vector

Even if only one value is written in the R language, it becomes a vector with a length of 1 and belongs to one of the above vector types.

# Atomic vector of type character.
print("abc");

# Atomic vector of type double.
print(12.5)

# Atomic vector of type integer.
print(63L)

# Atomic vector of type logical.
print(TRUE)

# Atomic vector of type complex.
print(2+3i)

# Atomic vector of type raw.
print(charToRaw('hello'))

When we execute the code above, it produces the following results -

[1] "abc"
[1] 12.5
[1] 63
[1] TRUE
[1] 2+3i
[1] 68 65 6c 6c 6f

Multi-element vector

Use a colon operator for numeric data

# Creating a sequence from 5 to 13.
v <- 5:13
print(v)

# Creating a sequence from 6.6 to 12.6.
v <- 6.6:12.6
print(v)

# If the final element specified does not belong to the sequence then it is discarded.
v <- 3.8:11.4
print(v)

When we execute the code above, it produces the following results -

[1]  5  6  7  8  9 10 11 12 13
[1]  6.6  7.6  8.6  9.6 10.6 11.6 12.6
[1]  3.8  4.8  5.8  6.8  7.8  8.8  9.8 10.8

Use sequence (Seq.) The sequence operator

# Create vector with elements from 5 to 9 incrementing by 0.4.
print(seq(5, 9, by = 0.4))

When we execute the code above, it produces the following results -

[1] 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8 8.2 8.6 9.0

Use the C() function

If one of the elements is a character, the non-character value is cast to the character type.

# The logical and numeric values are converted to characters.
s <- c('apple','red',5,TRUE)
print(s)

When we execute the code above, it produces the following results -

[1] "apple" "red"   "5"     "TRUE" 

Access vector elements

Use the index to access the elements of the vector. P arenthesis is used to index. T he index starts at position 1. G iving a negative value in the index discards the value from the result . RUE, FALSE, or 0 and 1 can also be used for indexing.

# Accessing vector elements using position.
t <- c("Sun","Mon","Tue","Wed","Thurs","Fri","Sat")
u <- t[c(2,3,6)]
print(u)

# Accessing vector elements using logical indexing.
v <- t[c(TRUE,FALSE,FALSE,FALSE,FALSE,TRUE,FALSE)]
print(v)

# Accessing vector elements using negative indexing.
x <- t[c(-2,-5)]
print(x)

# Accessing vector elements using 0/1 indexing.
y <- t[c(0,0,0,0,0,0,1)]
print(y)

When we execute the code above, it produces the following results -

[1] "Mon" "Tue" "Fri"
[1] "Sun" "Fri"
[1] "Sun" "Tue" "Wed" "Fri" "Sat"
[1] "Sun"

Vector operation

Vector operations

You can add, subtract, multiply, or divide two vectors of the same length, and output the result as a vector.

# Create two vectors.
v1 <- c(3,8,4,5,0,11)
v2 <- c(4,11,0,8,1,2)

# Vector addition.
add.result <- v1+v2
print(add.result)

# Vector substraction.
sub.result <- v1-v2
print(sub.result)

# Vector multiplication.
multi.result <- v1*v2
print(multi.result)

# Vector division.
divi.result <- v1/v2
print(divi.result)

When we execute the code above, it produces the following results -

[1]  7 19  4 13  1 13
[1] -1 -3  4 -3 -1  9
[1] 12 88  0 40  0 22
[1] 0.7500000 0.7272727       Inf 0.6250000 0.0000000 5.5000000

Vector element recycling

If we apply arithmetic to two vectors that are not equally long, the elements of the shorter vectors are looped to complete the operation.

v1 <- c(3,8,4,5,0,11)
v2 <- c(4,11)
# V2 becomes c(4,11,4,11,4,11)

add.result <- v1+v2
print(add.result)

sub.result <- v1-v2
print(sub.result)

When we execute the code above, it produces the following results -

[1]  7 19  8 16  4 22
[1] -1 -3  0 -6 -4  0

Vector elements are sorted

Elements in vectors can be sorted using the sort() function.

v <- c(3,8,4,5,0,11, -9, 304)

# Sort the elements of the vector.
sort.result <- sort(v)
print(sort.result)

# Sort the elements in the reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)

# Sorting character vectors.
v <- c("Red","Blue","yellow","violet")
sort.result <- sort(v)
print(sort.result)

# Sorting character vectors in reverse order.
revsort.result <- sort(v, decreasing = TRUE)
print(revsort.result)

When we execute the code above, it produces the following results -

[1]  -9   0   3   4   5   8  11 304
[1] 304  11   8   5   4   3   0  -9
[1] "Blue"   "Red"    "violet" "yellow"
[1] "yellow" "violet" "Red"    "Blue"