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

A quick and easy Tidyverse solution to get a NA count for all columns is to use summarise_all() which I think makes a much easier to read solution than using purrr or sapply

library(tidyverse)
# Example data
df <- tibble(col1 = c(1, 2, 3, NA), 
             col2 = c(NA, NA, "a", "b"))

df %>% summarise_all(~ sum(is.na(.)))
#> # A tibble: 1 x 2
#>    col1  col2
#>    
#> 1     1     2