Data: list only numeric values

How to list only numeric variables?

List all the variables

names(mtcars)

##  [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"   "gear"
## [11] "carb"

Variable and format

sapply(mtcars, class)

##       mpg       cyl      disp        hp      drat        wt      qsec        vs 
## "numeric" "numeric" "numeric" "numeric" "numeric" "numeric" "numeric" "numeric" 
##        am      gear      carb 
## "numeric" "numeric" "numeric"

Only numeric variables

sapply(mtcars, is.numeric)

##  mpg  cyl disp   hp drat   wt qsec   vs   am gear carb 
## TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE

# Which can be also condition:
names(which(sapply(mtcars, is.numeric)))

##  [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"   "gear"
## [11] "carb"

List variables which are not gear or carb but are numeric.

names(which(sapply(mtcars[ , !(names(mtcars) %in% c("gear", "carb"))], is.numeric)))

## [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"