Looping a pipe through columns of a tibble

January 9, 2022

I have a tibble with 20 variables. So far I’ve been using this pipe to find out which values appear more than once in a single column

as_tibble(iris) %>% group_by(Petal.Length) %>% summarise(n=sum(n())) %>% filter(n>1)

I was wonering if I could write a line that could loop this through all the columns and return 20 different tibbles (or as many as I need in the future) in the same way the pipe above would return one tibble. I have tried writing my own loops but I’ve had no success, I am quite new.

The iris example dataset has 5 columns so feel free to give an answer with 5 columns.

Thank you!

>Solution :

library(dplyr)

col_names <- colnames(iris)

lapply(
  col_names,
  function(col) {
    iris %>%
      group_by_at(col) %>%
      summarise(n = n()) %>% 
      filter(n > 1)
  }
)