prudence.R
In duckplyr: A 'DuckDB'-Backed Version of 'dplyr'

## ----include = FALSE----------------------------------------------------------
clean_output <- function(x, options) {
  x <- gsub("0x[0-9a-f]+", "0xdeadbeef", x)
  x <- gsub("dataframe_[0-9]*_[0-9]*", "      dataframe_42_42      ", x)
  x <- gsub("[0-9]*\\.___row_number ASC", "42.___row_number ASC", x)
  x <- gsub("─", "-", x)
  x
}

local({
  hook_source <- knitr::knit_hooks$get("document")
  knitr::knit_hooks$set(document = clean_output)
})

knitr::opts_chunk$set(
  collapse = TRUE,
  eval = identical(Sys.getenv("IN_PKGDOWN"), "true") || (getRversion() >= "4.1" && rlang::is_installed(c("conflicted", "nycflights13"))),
  comment = "#>"
)

Sys.setenv(DUCKPLYR_FALLBACK_COLLECT = 0)

## ----attach-------------------------------------------------------------------
# library(conflicted)
# library(dplyr)
# conflict_prefer("filter", "dplyr")

## -----------------------------------------------------------------------------
# df <-
#   duckplyr::duckdb_tibble(x = 1:3) |>
#   mutate(y = x + 1)
# df
# 
# class(df)
# 
# df$y
# 
# nrow(df)

## -----------------------------------------------------------------------------
# flights <- duckplyr::flights_df()
# 
# flights_duckdb <-
#   flights |>
#   duckplyr::as_duckdb_tibble()
# 
# system.time(
#   mean_arr_delay_ewr <-
#     flights_duckdb |>
#     filter(origin == "EWR", !is.na(arr_delay)) |>
#     summarize(
#       .by = month,
#       mean_arr_delay = mean(arr_delay),
#       min_arr_delay = min(arr_delay),
#       max_arr_delay = max(arr_delay),
#       median_arr_delay = median(arr_delay),
#     )
# )

## -----------------------------------------------------------------------------
# mean_arr_delay_ewr |>
#   explain()

## -----------------------------------------------------------------------------
# system.time(mean_arr_delay_ewr$mean_arr_delay[[1]])

## -----------------------------------------------------------------------------
# system.time(
#   flights |>
#     filter(origin == "EWR", !is.na(arr_delay)) |>
#     summarize(
#       .by = c(month, day),
#       mean_arr_delay = mean(arr_delay),
#       min_arr_delay = min(arr_delay),
#       max_arr_delay = max(arr_delay),
#       median_arr_delay = median(arr_delay),
#     )
# )

## -----------------------------------------------------------------------------
# flights_stingy <-
#   flights |>
#   duckplyr::as_duckdb_tibble(prudence = "stingy")

## -----------------------------------------------------------------------------
# flights_stingy
# 
# names(flights_stingy)[1:10]
# 
# class(flights_stingy)
# 
# class(flights_stingy[[1]])

## ----error = TRUE-------------------------------------------------------------
try({
# nrow(flights_stingy)
# 
# flights_stingy[[1]]
})

## ----error = TRUE-------------------------------------------------------------
try({
# flights_stingy |>
#   group_by(origin) |>
#   summarize(n = n()) |>
#   ungroup()
})

## -----------------------------------------------------------------------------
# flights_stingy |>
#   duckplyr::as_duckdb_tibble(prudence = "lavish") |>
#   group_by(origin) |>
#   summarize(n = n()) |>
#   ungroup()

## -----------------------------------------------------------------------------
# flights_stingy |>
#   duckplyr::as_duckdb_tibble(prudence = "lavish") |>
#   class()
# 
# flights_stingy |>
#   collect() |>
#   class()

## -----------------------------------------------------------------------------
# flights_stingy |>
#   as_tibble() |>
#   class()
# 
# flights_stingy |>
#   as.data.frame() |>
#   class()

## -----------------------------------------------------------------------------
# nrow(flights)
# flights_partial <-
#   flights |>
#   duckplyr::as_duckdb_tibble(prudence = "thrifty")

## ----error = TRUE-------------------------------------------------------------
try({
# flights_partial |>
#   select(origin, dest, dep_delay, arr_delay) |>
#   nrow()
})

## -----------------------------------------------------------------------------
# flights_partial |>
#   count(origin) |>
#   nrow()