Returns a dataframe with boxplot calculations

Source: R/boxplot.R

Uses dplyr operations to create boxplot calculations. Because of this approach, the calculations automatically run inside the database if `data` has a database or sparklyr connection. The `class()` of such tables in R are: tbl_sql, tbl_dbi, tbl_spark

Requires database support for percentile/quantile functions. Confirmed to work with:

  • Spark/Hive (via sparklyr) - uses percentile_approx()

  • SQL Server (2012+) - uses PERCENTILE_CONT()

  • PostgreSQL (9.4+) - uses percentile_cont()

  • Oracle (9i+) - uses PERCENTILE_CONT()

Does NOT work with SQLite, MySQL < 8.0, or MariaDB (no percentile support).

Note that this function supports input tbl that already contains grouping variables. This can be useful when creating faceted boxplots.

db_compute_boxplot(data, x, var, coef = 1.5)

Arguments

data

A table (tbl) that can already contain grouping variables

x

A discrete variable in which to group the boxplots

var

A continuous variable

coef

Length of the whiskers as multiple of IQR. Defaults to 1.5

Examples


mtcars |>
  db_compute_boxplot(am, mpg)
#> # A tibble: 2 × 12
#>      am     n lower middle upper max_raw min_raw   iqr min_iqr max_iqr  ymax
#>   <dbl> <int> <dbl>  <dbl> <dbl>   <dbl>   <dbl> <dbl>   <dbl>   <dbl> <dbl>
#> 1     0    19  15.0   17.3  19.2    24.4    10.4  6.38    8.57    25.6  24.4
#> 2     1    13  21     22.8  30.4    33.9    15   14.1     6.9     44.5  33.9
#> # ℹ 1 more variable: ymin <dbl>