How do I get the months with the highest average departure time for each airline from this dataset?

[jseddy72]

"For each airlines find the month where the average departure time is the highest in the year." I have the table built with the airline name, month, and average departure time but I don't know how to select out what I want.

library("nycflights13")
library(tidyverse)
dffl= flights
dfa=airlines
dfall <- merge(dfa, dffl, by ="carrier")

dfall %>%
  group_by(name, month) %>%
  summarise(mean_dt= mean(dep_time)) %>%
  arrange(desc(mean_dt))

Ive tried adding select(max(mean_dt)) but then it says mean_dt not found.

[jseddy72]

I believe I figured it out.

library("nycflights13")
library(tidyverse)
library(dplyr)
dffl= flights
dfa=airlines
dfall <- merge(dfa, dffl, by ="carrier")

dfall %>%
  group_by(name, month) %>%
  summarise(mean_dt= mean(dep_time)) %>%
  arrange(desc(mean_dt))%>%
  slice_max(mean_dt)

[dephilli]

You want to make a small adjustment to your code.

summarise(mean_dt= mean(dep_time)) %>%

This line is giving you some trouble and is returning NA for any cancelled flight. So, if Delta cancels a flight in February, you have no February Delta data.

summarise(mean_dt= mean(dep_time, rm.na=TRUE)) %>%

Adding rm.na=TRUE will filter out all the NA values in dep_time.