Count how many values in some cells of a row are not NA (in R)

Question

I\'ve got a data frame with lots of columns. For each row of the data frame, I\'d like to get a count of how many columns are NA. The problem is that I\'m only interested in

Answer 1

library(dplyr)
library(stringr)

df  <- data_frame(
  id = 1:10
  , name = fruit[1:10]
  , word1 = c(words[1:5],NA,words[7:10])
  , word2 = words[11:20]
  , word3 = c(NA,NA,NA,words[25],NA,NA,words[32],NA,NA,words[65])
) 

library(purrr)
# Rowwise sum of NAs
df %>% by_row(~ sum(is.na(.)), .collate = 'cols')

# Rowwise sum of non-NAs for word columns
df %>% 
  select(starts_with('word')) %>% 
  by_row(~ sum(!is.na(.)), .collate = 'cols')