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## ---- message = FALSE---------------------------------------------------------
library(dplyr)
con <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
flights <- copy_to(con, nycflights13::flights)
airports <- copy_to(con, nycflights13::airports)
## -----------------------------------------------------------------------------
flights %>%
select(contains("delay")) %>%
show_query()
flights %>%
select(distance, air_time) %>%
mutate(speed = distance / (air_time / 60)) %>%
show_query()
## -----------------------------------------------------------------------------
flights %>%
filter(month == 1, day == 1) %>%
show_query()
## -----------------------------------------------------------------------------
flights %>%
arrange(carrier, desc(arr_delay)) %>%
show_query()
## -----------------------------------------------------------------------------
flights %>%
group_by(month, day) %>%
summarise(delay = mean(dep_delay, na.rm = TRUE)) %>%
show_query()
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