lt_group: Define Row Groups

In lt: Lightweight Tables via JSON Specs and JavaScript

Define Row Groups

Description

Partition rows into labeled groups. Pass column names to group by those columns' values (the columns are removed from the body and rendered as rowspan cells on the left). Use sep = TRUE to render groups as full-width separator rows instead of rowspan.

Usage

lt_group(x, ..., sep = "auto", sort = TRUE)

Arguments

x	An lt() object.
...	A column name or formula (e.g., ~col or ~col1 + col2) to group by column values, or named arguments of the form "Label" = rows (integer vector of 1-based row indices) for manual groups. Unnamed character strings reorder previously defined groups.
sep	If TRUE, render groups as full-width separator rows instead of the default rowspan style. Only supports a single grouping column. The default 'auto' uses separator rows when there is a single character grouping column with any value longer than 20 characters (numeric columns always use rowspan).
sort	If TRUE (default), sort rows by group columns so that identical group values are contiguous. Set to FALSE to preserve the original row order.

Value

x with the row groups recorded.

Examples

# Group by a column (rowspan, default)
d = data.frame(arm = c("Placebo", "Placebo", "Treatment", "Treatment"),
               stat = c("n", "Mean", "n", "Mean"), value = c(30, 4.2, 31, 6.8))
lt(d) |> lt_group(~ arm)

# Separator-row style
lt(d) |> lt_group(~ arm, sep = TRUE)

# Manual groups (always separator rows)
lt(head(mtcars)) |>
  lt_group("First three" = 1:3, "Last three" = 4:6)

lt documentation built on July 10, 2026, 1:09 a.m.