row_count.R

library(purrr)
library(dplyr)

row_count <- function(.x, .f){ 
  .f <- as_mapper(.f)
  reduce(.x, function(x, y) x + .f(y), .init = 0 ) 
}

data <- tribble( 
  ~x, ~y, ~z, 
  1, 2, 3, 
  0, 2, 3, 
  0, 0, 0, 
  4, 5, 5
)

data

data %>% 
  row_count( ~ . > 2)