The right way to check for NAs

To check for missing values in R you might be tempted to use the equality operator == with your vector on one side and NA on the other. Don’t!

If you insist, you’ll get a useless results.

x <- c(1, NA, 3)
x == NA

## [1] NA NA NA

Instead use the is.na() function.

is.na(x)

## [1] FALSE  TRUE FALSE