Apply Horizontal Rules

Sets horizontal rules (lines) for the table using a named preset or custom rule properties. Calling fr_hlines() again replaces all previously set horizontal rules.

Usage

fr_hlines(
  spec,
  preset = "header",
  width = NULL,
  color = NULL,
  linestyle = NULL
)

Arguments

spec

An fr_spec object from fr_table().

preset

Named rule preset. One of:

"header" — single rule below the column header only. Default and most common in TFL outputs (ICH E3). No top or bottom border; footnotes follow the last body row directly.
"open" — rule above header + rule below header; no bottom border. Use when the table bottom is immediately followed by footnotes.
"hsides" — rule at the top (above header) and bottom (below body) only.
"above" — single rule above the column header only.
"below" — single rule below the last body row only.
"box" — full outer border on all four sides.
"booktabs" — thick top (1 pt) + thin mid (0.5 pt) + thick bottom (1 pt). The standard for PDF and publication output.
"void" — no horizontal rules. Clears all previously set rules.

width

Rule width. Named shorthand or numeric in points:

"hairline" = 0.25 pt
"thin" = 0.5 pt (default preset width)
"medium" = 1.0 pt
"thick" = 1.5 pt
Numeric, e.g. width = 0.75 (positive, in pt)

When supplied, overrides the preset's default widths for all rules created by this call. NULL uses each preset's own default widths.

color

Rule colour: hex string ("#003366") or CSS named colour ("navy"). NULL = black ("#000000").

linestyle

Rule line style. One of "solid" (default), "dashed", "dotted", "dashdot", or "double".

Value

A modified fr_spec. Rules stored in spec$rules.

Regulatory conventions

Most pharma TFL outputs use "header": a single thin solid rule separating column headers from body. No top or bottom border. Footnotes are placed directly below the last body row with a short separator line drawn by the footnote block itself (controlled by the .separator argument of fr_footnotes()).

"booktabs" is the standard for PDF/publication output and matches the LaTeX \toprule / \midrule / \bottomrule pattern.

Tips

Combine fr_hlines() and fr_vlines() independently — each manages its own set of rules.
fr_hlines("void") clears only horizontal rules; vertical rules from fr_vlines() are not affected.
width, color, and linestyle apply uniformly to all rules created by this preset call. For mixed widths (e.g. booktabs thick/thin), omit width and let the preset define its own widths.

Examples

## ── Common presets ────────────────────────────────────────────────────────

# Standard TFL output: single rule under column header
tbl_demog |> fr_table() |> fr_hlines("header")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

# Open: header rules, no bottom border
tbl_demog |> fr_table() |> fr_hlines("open")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 2 hline(s)

# Booktabs: publication-quality thick/thin/thick
tbl_demog |> fr_table() |> fr_hlines("booktabs")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 3 hline(s)

# Top and bottom rules only
tbl_demog |> fr_table() |> fr_hlines("hsides")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 2 hline(s)

# Box: full outer border
tbl_demog |> fr_table() |> fr_hlines("box")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules:

# Remove all horizontal rules
tbl_demog |> fr_table() |> fr_hlines("void")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom

## ── Custom width ─────────────────────────────────────────────────────────

# Hairline rules (0.25 pt)
tbl_demog |> fr_table() |> fr_hlines("header", width = "hairline")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

# Thick rules (1.5 pt)
tbl_demog |> fr_table() |> fr_hlines("hsides", width = "thick")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 2 hline(s)

# Exact width in points
tbl_demog |> fr_table() |> fr_hlines("header", width = 0.75)
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

## ── Custom colour (hex or CSS named colour) ────────────────────────────────

# Hex colour
tbl_demog |> fr_table() |> fr_hlines("booktabs", color = "#003366")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 3 hline(s)

# CSS named colour
tbl_demog |> fr_table() |> fr_hlines("header", color = "steelblue")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

## ── Custom linestyle ──────────────────────────────────────────────────────

# Dashed rule below header
tbl_demog |> fr_table() |> fr_hlines("header", linestyle = "dashed")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

# Double rule below header
tbl_demog |> fr_table() |> fr_hlines("header", linestyle = "double")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

# Dash-dot (SAS ODS equivalent)
tbl_demog |> fr_table() |> fr_hlines("header", linestyle = "dashdot")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Header: valign=bottom
#> Rules: 1 hline(s)

## ── Full pipeline ─────────────────────────────────────────────────────────

tbl_demog |>
  fr_table() |>
  fr_titles("Table 14.1.1 Demographics", "Full Analysis Set") |>
  fr_footnotes("[a] Percentages based on N in column header.") |>
  fr_hlines("header") |>
  fr_vlines("box")
#> 
#> ── fr_spec: Table 
#> Data: 28 rows x 6 columns
#> Page: landscape letter, 9pt Courier New
#> Titles (2):
#> 1. [center] "Table 14.1.1 Demographics"
#> 2. [center] "Full Analysis Set"
#> Header: valign=bottom
#> Rules: 1 hline(s)
#> Footnotes (1):
#> 1. [left] "[a] Percentages based on N in column header."