Merge functions

Merge cells horizontally or vertically in a flextable.

flextable provides several functions to merge adjacent cells. Merged cells display only the content of the first cell in the merged range.

Quick reference

Function	What it does
merge_h(x, i, part)	Merge identical adjacent cells horizontally
merge_v(x, j, part)	Merge identical adjacent cells vertically
merge_at(x, i, j, part)	Merge a specific rectangular range
merge_h_range(x, i, j1, j2, part)	Merge a column range for selected rows
merge_none(x)	Remove all merges

"all" is not a valid value for part in merge functions.

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merge_h()

Merges consecutive cells in the same row that have identical formatted values.

merge_h(x, i = NULL, part = "body")

x · flextable · required

A flextable object.

i · integer | formula | logical

Row selector. NULL processes all rows.

part · string · default: "\"body\""

Which part to process: "body", "header", or "footer".

Example

library(flextable)

schedule <- data.frame(
  time = c("9h", "10h", "11h", "14h", "15h", "16h"),
  monday    = c("Math", "Math", "French", "History", "Science", "French"),
  tuesday   = c("English", "Math", "Art", "Math", "Math", "French"),
  wednesday = c("Science", "Math", "Science", "English", "English", "French"),
  stringsAsFactors = FALSE
)

ft <- flextable(schedule)
ft <- theme_box(ft)
ft <- merge_h(ft)
ft

---

merge_v()

Merges consecutive cells in the same column that have identical formatted values.

merge_v(x, j = NULL, target = NULL, part = "body", combine = FALSE)

x · flextable · required

A flextable object.

j · integer | character

Column selector that controls which columns are inspected for consecutive identical values.

target · character

Column names where the merge should actually be applied. Useful when you want to trigger a merge based on one column’s values but apply it to additional columns. If NULL, defaults to the columns selected by j.

part · string · default: "\"body\""

Which part to process: "body", "header", or "footer".

combine · logical · default: "FALSE"

If TRUE, the columns in j are combined into a single composite key before checking for consecutive identical values. If FALSE, each column is inspected independently.

Example

Merge vertically on two columns:

ft <- flextable(mtcars)
ft <- merge_v(ft, j = c("gear", "carb"))
ft

Merge based on one column but apply the span to additional target columns:

ft <- flextable(data_ex)
ft <- theme_box(ft)
ft <- merge_v(ft,
  j = "srdr_id",
  target = c("srdr_id", "substances")
)
ft

---

merge_at()

Merges all cells in a specified rectangular range into a single cell. All selected rows and columns must be consecutive.

merge_at(x, i = NULL, j = NULL, part = "body")

x · flextable · required

A flextable object.

i · integer | formula | logical

Row selector.

j · integer | character

Column selector.

part · string · default: "\"body\""

Which part to process: "body", "header", or "footer".

Example

ft <- flextable(head(mtcars), cwidth = .5)
ft <- merge_at(ft, i = 1:2, j = 1:2)
ft

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merge_h_range()

Merges a consecutive range of columns into a single cell for each selected row. Both j1 and j2 must define consecutive columns.

merge_h_range(x, i = NULL, j1 = NULL, j2 = NULL, part = "body")

x · flextable · required

A flextable object.

i · integer | formula | logical

Row selector.

j1 · integer | character

The first (leftmost) column of the merge range.

j2 · integer | character

The last (rightmost) column of the merge range.

part · string · default: "\"body\""

Which part to process: "body", "header", or "footer".

Example

ft <- flextable(head(mtcars), cwidth = .5)
ft <- theme_box(ft)
ft <- merge_h_range(ft, i = ~ cyl == 6, j1 = "am", j2 = "carb")
ft <- align(ft, i = ~ cyl == 6, align = "center")
ft

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merge_none()

Removes all cell merging information from a flextable, restoring each cell to independent display.

merge_none(x)

x · flextable · required

A flextable object.

Example

ft <- flextable(head(iris))
ft <- set_header_df(ft, mapping = typology, key = "col_keys")
ft <- merge_v(ft, j = c("Species"))
ft <- theme_tron_legacy(merge_none(ft))
ft

See also

• valign() — set vertical alignment within merged cells
• align() — set horizontal alignment