In R, how to combine dplyr transformations for nycflights13-CodePudding

I am trying to find the five shortest minimum distances, called min_dist, by origin/destination in the nycflights13 package in R Studio. The result should be a tibble with 5 rows and 3 columns(origin, dest, and min_dist).

I am a beginner and this is what I have so far:

Q3 <- flights %>%
           
arrange(flights, distance)
group_by(origin) %>% 
summarise(min_dist = origin/dest)

I am getting the error: Error in group_by(origin) : object 'origin' not found. Any hints on what to do? A lot of the other questions are similar to this so I want to figure out how to do these. Thank you

CodePudding user response：

This may be done by selecting the columns of interest, get the distinct rows and apply the slice_min with n = 5

library(dplyr)
flights %>%
  select(origin, dest, min_distance = distance)%>% 
  distinct %>% 
  slice_min(n = 5, order_by = min_distance, with_ties = FALSE)

-output

# A tibble: 5 × 3
  origin dest  min_distance
  <chr>  <chr>        <dbl>
1 EWR    LGA             17
2 EWR    PHL             80
3 JFK    PHL             94
4 LGA    PHL             96
5 EWR    BDL            116

CodePudding user response：

We could use top_n with negative sign:

library(nycflights13)
library(dplyr)

flights %>%
  select(origin, dest, distance) %>% 
  distinct() %>% 
  top_n(-5) %>% 
  arrange(distance)

  origin dest  distance
  <chr>  <chr>    <dbl>
1 EWR    LGA         17
2 EWR    PHL         80
3 JFK    PHL         94
4 LGA    PHL         96
5 EWR    BDL        116