Filter and select dataset in r

Question

Using the mtcar dataset I want to find the top 2 cars with the highest mileage and after knowing that information I want to create a new data frame that has info of only those 2 cars with all the remaining info like horsepower, gear, cylinder, and so on. Please let me know how could I do that

cars<-mtcars %>% 
          group_by(mpg) %>% 
          count(mpg)

So with this, I get 32.9 and 32.4 as best mpg now how do I add all the other info in a new data frame that has info about these 2 cars. Please let me know. Thank you!

`dplyr::count` counts how many times a group occurs. It's not going to give you a maximum value — camille, Sep 21 '21 at 02:12
Also see https://stackoverflow.com/q/27766054/5325862, https://stackoverflow.com/q/63793757/5325862, and https://stackoverflow.com/q/53994497/5325862 — camille, Sep 21 '21 at 02:21

score 1 · Answer 1 · answered Sep 21 '21 at 00:20

We may use slice_max

library(dplyr)
mtcars %>% 
    slice_max(n = 2, order_by = "mpg")

Or use arrange and slice

mtcars %>% 
    arrange(desc(mpg)) %>%
    slice_head(n = 2)

-output

                 mpg cyl disp hp drat    wt  qsec vs am gear carb
Toyota Corolla 33.9   4 71.1 65 4.22 1.835 19.90  1  1    4    1
Fiat 128       32.4   4 78.7 66 4.08 2.200 19.47  1  1    4    1

score 1 · Accepted Answer · answered Sep 21 '21 at 02:55

You could use top_n from dplyr.

library(dplyr)

top2mpg <- mtcars %>% top_n(2, mpg)

	mpg	cyl	disp	hp	drat	wt	qsec	vs	am	gear	carb	FIELD13
Fiat	128	32.4	4	78.7	66	4.08	2.200	19.47	1	1	4	1
Toyota	Corolla	33.9	4	71.1	65	4.22	1.835	19.90	1	1	4	1

Filter and select dataset in r

2 Answers2