Determine the number of NA values in a column

Question

I want to count the number of NA values in a data frame column. Say my data frame is called df, and the name of the column I am considering is

Answer 1

Similar to hute37's answer but using the purrr package. I think this tidyverse approach is simpler than the answer proposed by AbiK.

library(purrr)
map_dbl(df, ~sum(is.na(.)))

Note: the tilde (~) creates an anonymous function. And the '.' refers to the input for the anonymous function, in this case the data.frame df.