I have a flagging rule need to apply.
Here is how my dataset looks like:
df <- data.frame(id = c(1,1,1,1, 2,2,2,2, 3,3,3,3),
key = c("a","a","b","c", "a","b","c","d", "a","b","c","c"),
form = c("A","B","A","A", "A","A","A","A", "B","B","B","A"))
> df
id key form
1 1 a A
2 1 a B
3 1 b A
4 1 c A
5 2 a A
6 2 b A
7 2 c A
8 2 d A
9 3 a B
10 3 b B
11 3 c B
12 3 c A
I would like to flag ids based on a key columns that has duplicates, a third column of form shows different forms for each key. The idea is to understand if an id has taken any items from multiple forms. I need to add a filtering column as below:
> df.1
id key form type
1 1 a A multiple
2 1 a B multiple
3 1 b A multiple
4 1 c A multiple
5 2 a A single
6 2 b A single
7 2 c A single
8 2 d A single
9 3 a B multiple
10 3 b B multiple
11 3 c B multiple
12 3 c A multiple
And eventually I need to get rid off the extra duplicated row which has different form. To decide which of the duplicated one drops, I pick whichever the form type has more items.
In a final separate dataset, I would like to have something like below:
> df.2
id key form type
1 1 a A multiple
3 1 b A multiple
4 1 c A multiple
5 2 a A single
6 2 b A single
7 2 c A single
8 2 d A single
9 3 a B multiple
10 3 b B multiple
11 3 c B multiple
So first id has form A dominant so kept the A, and the third id has form B dominant so kept the B.
Any ideas? Thanks!
We can check number of distinct elements to create the new column by group and then filter based on the highest frequency (Mode)
library(dplyr)
df.2 <- df %>%
group_by(id) %>%
mutate(type = if(n_distinct(form) > 1) 'multiple' else 'single') %>%
filter(form == Mode(form)) %>%
ungroup
-output
> df.2
# A tibble: 10 × 4
id key form type
<dbl> <chr> <chr> <chr>
1 1 a A multiple
2 1 b A multiple
3 1 c A multiple
4 2 a A single
5 2 b A single
6 2 c A single
7 2 d A single
8 3 a B multiple
9 3 b B multiple
10 3 c B multiple
where
Mode <- function(x) {
ux <- unique(x)
ux[which.max(tabulate(match(x, ux)))]
}