Numeric data

Example: 1, 2, 3, ...

x <- c(1, 2, 3)
x
## [1] 1 2 3
is.numeric(x)
## [1] TRUE
as.character(x)
## [1] "1" "2" "3"

Character data

Example: "a", "b", "c", ...

x <- c("1", "2", "3")
x
## [1] "1" "2" "3"
is.character(x)
## [1] TRUE
as.numeric(x)
## [1] 1 2 3

Complex data

Example: mix of both

c(1, "b", 3)
## [1] "1" "b" "3"

Logical data

Example: TRUE of FALSE

x <- 1:10 < 5
x  
##  [1]  TRUE  TRUE  TRUE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE
!x
##  [1] FALSE FALSE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
which(x) # Returns index for the 'TRUE' values in logical vector
## [1] 1 2 3 4