split_rows_by_multivar: Associate multiple variables with rows

In rtables: Reporting Tables

Associate multiple variables with rows

Description

When we need rows to reflect different variables rather than different levels of a single variable, we use split_rows_by_multivar.

Usage

split_rows_by_multivar(
  lyt,
  vars,
  split_fun = NULL,
  split_label = "",
  varlabels = vars,
  parent_name = "multivars",
  format = NULL,
  na_str = NA_character_,
  nested = TRUE,
  at_sibling = NULL,
  child_labels = c("default", "visible", "hidden"),
  indent_mod = 0L,
  section_div = NA_character_,
  extra_args = list()
)

Arguments

lyt	(PreDataTableLayouts) layout object pre-data used for tabulation.
vars	(character) vector of variable names.
split_fun	(function or NULL) custom splitting function. See custom_split_funs.
split_label	(string) label to be associated with the table generated by the split. Not to be confused with labels assigned to each child (which are based on the data and type of split during tabulation).
varlabels	(character) vector of labels for vars.
parent_name	(character(1)) Name to assign to the table corresponding to the split or group of sibling analyses, for ⁠split_rows_by*⁠ and ⁠analyze*⁠ when analyzing more than one variable, respectively. Ignored when analyzing a single variable.
format	(string, function, or list) format associated with this split. Formats can be declared via strings ("xx.x") or function. In cases such as analyze calls, they can be character vectors or lists of functions. See formatters::list_valid_format_labels() for a list of all available format strings.
na_str	(string) string that should be displayed when the value of x is missing. Defaults to "NA".
nested	(logical) whether this layout instruction should be applied within the existing layout structure if possible (TRUE, the default) or as a new top-level element (FALSE). Ignored if it would nest a split underneath analyses, which is not allowed.
at_sibling	(character(1) or NULL) If non-null, a preceding split or analyze to anchor this instruction to as a direct sibling. Cannot select an instruction that is downstream of a point where a previously used anchor (See Nesting Anchor Resolution for details).
child_labels	(string) the display behavior for the labels (i.e. label rows) of the children of this split. Accepts "default", "visible", and "hidden". Defaults to "default" which flags the label row as visible only if the child has 0 content rows.
indent_mod	(numeric) modifier for the default indent position for the structure created by this function (subtable, content table, or row) and all of that structure's children. Defaults to 0, which corresponds to the unmodified default behavior.
section_div	(string) string which should be repeated as a section divider after each group defined by this split instruction, or NA_character_ (the default) for no section divider.
extra_args	(list) extra arguments to be passed to the tabulation function. Element position in the list corresponds to the children of this split. Named elements in the child-specific lists are ignored if they do not match a formal argument of the tabulation function.

Value

A PreDataTableLayouts object suitable for passing to further layouting functions, and to build_table().

Nesting Anchor Resolution

When nested is TRUE, at_sibling allows you to set a nesting anchor that your new ⁠split_rows_by*⁠ or ⁠analyze*⁠ directive should be placed as a sibling to. The lookup for this anchor occurs only in the currently active top-level nesting stack, meaning the directives that have occurred since the last split or analysis with nested == FALSE.

Furthermore, resolution occurs against the first element of each arm of a branching point caused by any previous uses of at_sibling but only descends into the last arm.

So for example if our previous layout was generated via:

lyt <- basic_table() |>
  split_rows_by("SEX") |>
  analyze("AGE") |>
  split_rows_by("BMRKR2", nested = FALSE) |>
  split_rows_by("RACE") |>
  analyze("AGE") |>
  split_rows_by("SEX", at_sibling = "RACE") |>
  analyze("BMRKR1")

The eligible anchor points would be "BMRKR2", "RACE", "SEX" and "BMRKR1". "AGE" is masked by the branching caused by anchoring our SEX split on RACE.

Finally, while at_sibling does support de-duplication of "<name>[i]" anchors, it does so within the set of available anchors, which can be counter-intuitive. It is strongly suggested that the parent_name and table_names argument(s) of ⁠split_rows_by*⁠ and analyze be used to prevent the need for this. at_sibling will resolve to table names overridden in this manner.

See Also

split_rows_by() for typical row splitting, and split_cols_by_multivar() to perform the same type of split on a column basis.

Examples

lyt <- basic_table() |>
  split_cols_by("ARM") |>
  split_rows_by_multivar(c("SEX", "STRATA1")) |>
  summarize_row_groups() |>
  analyze(c("AGE", "SEX"))

tbl <- build_table(lyt, DM)
tbl

rtables documentation built on Oct. 1, 2026, 9:07 a.m.