Removing NAs
We previously computed the average of na_example using mean(na_example) and obtain NA. This is because the function mean returns NA if it encounters at least one NA.
A common operation is therefore removing the entries that are NA and after that perform operations on the rest.
This exercise is part of the course
Data Science R Basics
Exercise instructions
Write one line of code to compute the average, but only for the entries that are not NA making use of the ! operator before ind. (Remember that you can use help("!") to find out more about what ! does.)
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Note what we can do with the ! operator
x <- c(1, 2, 3)
ind <- c(FALSE, TRUE, FALSE)
x[!ind]
# Create the ind vector
library(dslabs)
data(na_example)
ind <- is.na(na_example)
# We saw that this gives an NA
mean(na_example)
# Compute the average, for entries of na_example that are not NA