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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/davidgohel/flextable/llms.txt

Use this file to discover all available pages before exploring further.

flextable separates border control into high-level helpers for common patterns and lower-level functions for precise placement. All border styling requires an officer::fp_border() object to describe the line’s appearance.

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Defining a border style with fp_border()

fp_border() from the officer package describes a single border line: 
library(officer)

# Thin black border (1 pt)
thin <- fp_border(color = "black", width = 1, style = "solid")

# Thick red border (2 pt)
thick_red <- fp_border(color = "red", width = 2)

# No border (zero width)
none <- fp_border(width = 0)
fp_border_default() returns a border using the current flextable defaults: 
std <- fp_border_default()          # uses set_flextable_defaults() values
std2 <- fp_border_default(width = 2) # override width only

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Removing all borders

border_remove() sets every border in the table to zero width, across all parts: 
ft <- flextable(head(iris))
ft <- theme_box(ft)      # apply a style that adds many borders
ft <- border_remove(ft)  # strip them all
ft
This is frequently used as the first step when building a custom border scheme from scratch.

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Table-level border helpers

These functions apply borders to whole structural regions of the table.

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Outer borders

border_outer() frames the outside edge of one or all parts: 
library(officer)

big_border <- fp_border(color = "red", width = 2)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- border_outer(ft, part = "all", border = big_border)
ft

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Inner horizontal borders

border_inner_h() draws a horizontal line between every pair of adjacent rows: 
std_border <- fp_border(color = "orange", width = 1)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- border_inner_h(ft, border = std_border)
ft

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Inner vertical borders

border_inner_v() draws a vertical line between every pair of adjacent columns: 
std_border <- fp_border(color = "orange", width = 1)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- border_inner_v(ft, border = std_border)
ft

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All inner borders

border_inner() applies both horizontal and vertical inner borders in one call: 
std_border <- fp_border(color = "orange", width = 1)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- border_inner(ft, border = std_border)
ft

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Row-level horizontal lines

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hline() — horizontal line below selected rows

hline() draws a line below each selected row i. It sets both the bottom border of row i and the top border of row i + 1 to ensure consistent rendering: 
std_border <- fp_border(color = "gray")

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- hline(ft, part = "all", border = std_border)
ft
Target specific rows with the i selector: 
library(officer)

dat <- data.frame(
  Level = c("setosa", "versicolor", "virginica", "<NA>", "Total"),
  Freq  = as.integer(c(50, 50, 50, 0, 150))
)

ft <- flextable(dat)
ft <- hline(
  ft,
  i = ~ before(Level, "Total"),
  border = fp_border_default(width = 2)
)
ft
before(x, entries) returns a logical vector marking the rows immediately before the first occurrence of any of entries — a convenient way to insert a separator above a totals row.

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hline_top() — top border of a part

hline_top() draws a line at the very top of a table part: 
big_border <- fp_border(color = "orange", width = 3)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- hline_top(ft, part = "all", border = big_border)
ft

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hline_bottom() — bottom border of a part

hline_bottom() draws a line at the very bottom of a table part: 
big_border <- fp_border(color = "orange", width = 3)

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- hline_bottom(ft, part = "body", border = big_border)
ft

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Column-level vertical lines

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vline() — vertical line to the right of selected columns

vline() draws a line to the right of each selected column j. It sets the right border of column j and the left border of column j + 1: 
std_border <- fp_border(color = "orange")

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- vline(ft, border = std_border)
ft

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vline_left() and vline_right() — outer vertical edges

std_border <- fp_border(color = "orange")

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- vline_left(ft, border = std_border)
ft <- vline_right(ft, border = std_border)
ft

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Highlighting individual cells with surround()

surround() draws borders around specific cells without affecting the rest of the table: 
std_border <- fp_border(color = "orange")

ft <- flextable(head(iris))
ft <- border_remove(ft)
ft <- border_outer(ft, border = std_border)

for (id in 1:3) {
  ft <- bg(ft, i = id, j = id, bg = "yellow")
  ft <- surround(
    ft,
    i = id, j = id,
    border.left  = std_border,
    border.right = std_border,
    part = "body"
  )
}

ft <- autofit(ft)
ft

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Fixing border rendering issues

fix_border_issues() corrects a rendering artifact where adjacent cells from different table parts display doubled or mismatched borders in some output formats: 
ft <- flextable(head(airquality))
ft <- theme_vanilla(ft)
ft <- fix_border_issues(ft)
ft
All built-in theme functions call fix_border_issues() automatically. Call it explicitly only when you build a border scheme manually.

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Building a custom border scheme

1

Remove all existing borders

library(officer)
library(flextable)

ft <- flextable(head(mtcars))
ft <- border_remove(ft)
2

Define border styles

thick <- fp_border(color = "black", width = 2)
thin  <- fp_border(color = "black", width = 0.5)
3

Apply outer and inner borders

ft <- border_outer(ft, border = thick, part = "all")
ft <- border_inner_h(ft, border = thin, part = "all")
ft <- border_inner_v(ft, border = thin, part = "all")
4

Emphasize the header bottom

ft <- hline_bottom(ft, border = thick, part = "header")
5

Fix any rendering artifacts

ft <- fix_border_issues(ft)
ft

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Quick reference

FunctionWhat it does
border_remove(x)Remove all borders from all parts
border_outer(x, border, part)Set outer (perimeter) borders of a part
border_inner_h(x, border, part)Set inner horizontal borders
border_inner_v(x, border, part)Set inner vertical borders
border_inner(x, border, part)Set all inner borders
hline(x, i, border, part)Horizontal line below selected rows
hline_top(x, border, part)Top border of a part
hline_bottom(x, border, part)Bottom border of a part
vline(x, j, border, part)Vertical line to the right of selected columns
vline_left(x, border, part)Left edge of the table
vline_right(x, border, part)Right edge of the table
surround(x, i, j, border.*, part)Borders around individual cells
fix_border_issues(x)Correct rendering artifacts at part boundaries

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