R - less than operator example

The example below shows the usage of less than(<) operator in different scenarios.

Comparing with a scalar

If a vector or a matrix is compared with a scalar (single element atomic vector), it acts on each element of it and returns TRUE if the element is less than the scalar, else returns FALSE.

#first operand
x1 <- 10
v1 <- c(10, 20, 30)
m1 <- matrix(c(10, 20, 30, 40, 50, 60), nrow=2)

#second operand
x2 <- 20

#comparing two scalars
print(x1 < x2)
#comparing a vector with a scalar
print(v1 < x2)
#comparing a matrix with a scalar
cat("\n")
print(m1 < x2)

The output of the above code will be:

[1] TRUE
[1]  TRUE FALSE FALSE

      [,1]  [,2]  [,3]
[1,]  TRUE FALSE FALSE
[2,] FALSE FALSE FALSE

Comparing with a vector

When two vectors are compared, their length should be same or length of longer vector should be multiple of length of shorter vector. Similarly, when a vector is compared with a matrix, the length of longer object should be multiple of length of shorter object.

Please note that, When a vector is compared with a matrix, elements are compared column-wise.

#first operand
x1 <- 10
v1 <- c(10, 20, 30)
m1 <- matrix(c(10, 20, 30, 40, 50, 60), nrow=2)

#second operand
v2 <- c(10, 50, 100)

#comparing a scalar (single element 
#atomic vector) with a vector
print(x1 < v2)
#comparing two vectors
print(v1 < v2)
#comparing a matrix with a vector
cat("\n")
print(m1 < v2)

The output of the above code will be:

[1] FALSE  TRUE  TRUE
[1] FALSE  TRUE  TRUE

      [,1]  [,2]  [,3]
[1,] FALSE  TRUE FALSE
[2,]  TRUE FALSE  TRUE

Comparing with a matrix

When two matrices are compared, their dimension should be same or dimension of bigger matrix should be multiple of dimension of smaller matrix.

#first operand
x1 <- 10
v1 <- c(10, 20, 30)
m1 <- matrix(c(10, 20, 30, 40, 50, 60), nrow=2)

#second operand
m2 <- matrix(c(10, 20, 30, 100, 200, 300), nrow=2)

#comparing a scalar (single element 
#atomic vector) with a matrix
print(x1 < m2)
#comparing a vector with a matrix
cat("\n")
print(v1 < m2)
#comparing two matrices
cat("\n")
print(m1 < m2)

The output of the above code will be:

      [,1] [,2] [,3]
[1,] FALSE TRUE TRUE
[2,]  TRUE TRUE TRUE

      [,1]  [,2] [,3]
[1,] FALSE FALSE TRUE
[2,] FALSE  TRUE TRUE

      [,1]  [,2] [,3]
[1,] FALSE FALSE TRUE
[2,] FALSE  TRUE TRUE

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