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Every cell in a flextable contains exactly one paragraph. A paragraph is an ordered sequence of chunks — the smallest content units. You build a paragraph with as_paragraph() and set it in a cell with compose() (or its alias mk_par()).

​
How compose works

compose() replaces the displayed content of selected cells with a paragraph you define: 
library(flextable)

ft <- flextable(head(iris))
ft <- compose(
  ft,
  j     = "Sepal.Length",
  value = as_paragraph(
    "Length: ",
    as_chunk(Sepal.Length, props = fp_text_default(color = "red"))
  ),
  part = "body"
)
ft <- autofit(ft)
ft
The value argument must be a call to as_paragraph(). Row and column selectors (i, j) work the same way as in all other flextable functions. mk_par() is an alias for compose() provided because compose conflicts with purrr::compose(): 
ft <- mk_par(
  x     = ft,
  j     = "comment",
  i     = ~ dist > 9,
  value = as_paragraph(
    colorize(as_i("speed: "), color = "gray"),
    as_sup(sprintf("%.0f", speed))
  )
)

​
Using use_dot = TRUE

Set use_dot = TRUE to access the column’s own values as . inside the as_paragraph() call. This lets you reference a column by formula without spelling out its name: 
set.seed(8)
dat <- iris[sample.int(150, size = 10), ]
dat <- dat[order(dat$Species), ]

ft <- flextable(dat)
ft <- mk_par(ft,
  j        = ~ . - Species,
  value    = as_paragraph(
    minibar(., barcol = "white", height = .1)
  ),
  use_dot  = TRUE
)
ft <- theme_vader(ft)
ft <- autofit(ft)
ft

​
Building paragraphs with as_paragraph()

as_paragraph() assembles one or more chunk objects into a single paragraph. Plain character strings are automatically converted to chunks: 
ft <- flextable(airquality[sample.int(150, size = 10), ])
ft <- compose(ft,
  j     = "Wind",
  value = as_paragraph(
    as_chunk(Wind, props = fp_text_default(color = "orange")),
    " ",
    minibar(
      value  = Wind,
      max    = max(airquality$Wind),
      barcol = "orange",
      bg     = "black",
      height = .15
    )
  ),
  part = "body"
)
ft <- autofit(ft)
ft

​
Text chunks

​
as_chunk() — formatted text

as_chunk() converts a value to a text chunk with optional text properties: 
ft <- flextable(head(iris))
ft <- compose(ft,
  j     = "Sepal.Length",
  value = as_paragraph(
    "Sepal.Length value is ",
    as_chunk(Sepal.Length, props = fp_text_default(color = "red"))
  ),
  part = "body"
)
ft <- color(ft, color = "gray40", part = "all")
ft <- autofit(ft)
ft
The formatter argument accepts any function that turns x into a character vector. The default is format_fun, which applies sensible defaults for numbers and other types.

​
Inline style shortcuts

These chunk functions apply a single style property and accept either a raw value or an existing chunk object: 
ft <- compose(ft,
  j = "dummy",
  value = as_paragraph(as_b(Sepal.Length))
)
Sets bold = TRUE.

​
colorize() — font color

colorize() sets the text color of a chunk: 
ft <- compose(ft,
  j     = "dummy",
  value = as_paragraph(colorize(Sepal.Length, color = "red"))
)
It accepts any R color name or hex string and can wrap an existing chunk or a raw value.

​
as_highlight() — background highlight

as_highlight() sets the background (shading) color of a chunk: 
ft <- compose(ft,
  j     = "dummy",
  value = as_paragraph(as_highlight(Sepal.Length, color = "yellow"))
)

​
as_bracket() — parenthesized values

as_bracket() concatenates multiple values and wraps them in brackets. Useful for combining a mean and standard deviation: 
ft <- flextable(head(iris), col_keys = c("Species", "Sepal", "Petal"))
ft <- compose(ft,
  j     = "Sepal",
  value = as_paragraph(as_bracket(Sepal.Length, Sepal.Width))
)
ft <- compose(ft,
  j     = "Petal",
  value = as_paragraph(as_bracket(Petal.Length, Petal.Width))
)
ft
The default separator is ", " and the default brackets are ( and ). Override with sep, p, and s. hyperlink_text() creates a clickable link chunk: 
dat <- data.frame(
  col  = "Google it",
  href = "https://www.google.fr/search?source=hp&q=flextable+R+package",
  stringsAsFactors = FALSE
)

ftab <- flextable(dat)
ftab <- compose(
  x     = ftab,
  j     = "col",
  value = as_paragraph(
    "This is a link: ",
    hyperlink_text(x = col, url = href)
  )
)
ftab
URL encoding is not applied — the url value is passed through as-is.
Hyperlinks require the officedown package when rendering to Word (docx) in an R Markdown context.

​
Images

as_image() embeds an image file as a chunk inside a cell: 
img.file <- file.path(R.home("doc"), "html", "logo.jpg")

if (require("magick")) {
  ft <- flextable(head(iris))
  ft <- compose(ft,
    i     = 1:3,
    j     = 1,
    value = as_paragraph(
      as_image(src = img.file),
      " ",
      as_chunk(Sepal.Length, props = fp_text_default(color = "red"))
    ),
    part = "body"
  )
  ft <- autofit(ft)
  ft
}
Provide explicit width and height in inches, or set guess_size = TRUE (requires the magick package) to detect dimensions automatically.
PowerPoint cannot mix images and text in the same paragraph. Images are silently removed when outputting to .pptx.

​
Equations

as_equation() renders a MathJax equation inside a cell. It requires the equatags package and a one-time call to equatags::mathjax_install(): 
if (require("equatags")) {
  eqs <- c(
    "(ax^2 + bx + c = 0)",
    "a \\ne 0",
    "x = {-b \\pm \\sqrt{b^2-4ac} \\over 2a}"
  )
  df <- data.frame(formula = eqs)

  ft <- flextable(df)
  ft <- compose(
    x     = ft,
    j     = "formula",
    value = as_paragraph(as_equation(formula, width = 2, height = .5))
  )
  ft <- align(ft, align = "center", part = "all")
  ft <- width(ft, width = 2)
  ft
}

​
Word field codes

as_word_field() inserts a Word field code — such as PAGE or NumPages — as a chunk. Fields are only meaningful in Word (.docx) output; other formats ignore them. 
library(officer)

ft <- flextable(head(cars))
ft <- add_footer_lines(ft, "temp text")
ft <- compose(
  x     = ft,
  part  = "footer",
  i     = 1,
  j     = 1,
  value = as_paragraph(
    "p. ",
    as_word_field(x = "Page",     width = .05),
    " on ",
    as_word_field(x = "NumPages", width = .05)
  )
)
ft <- autofit(ft, part = c("header", "body"))
Fields are inserted but not computed at the time of writing. Open the document in Word and press F9 (macOS: Fn + F9) to refresh all field values.
You can also insert field codes via a post-processing hook to avoid applying them in non-Word output: 
pp_docx <- function(x) {
  x <- add_header_lines(x, "Page ")
  x <- append_chunks(
    x    = x,
    i    = 1,
    part = "header",
    j    = 1,
    as_word_field(x = "Page")
  )
  align(x, part = "header", align = "left")
}

# Apply only for Word output:
# set_flextable_defaults(post_process_docx = pp_docx)

​
Combining multiple chunk types

Chunks can be freely combined inside a single as_paragraph() call. The following example places italic gray label text alongside a superscripted numeric value: 
ft <- flextable(
  head(cars, n = 5),
  col_keys = c("speed", "dist", "comment")
)

ft <- mk_par(
  x     = ft,
  j     = "comment",
  i     = ~ dist > 9,
  value = as_paragraph(
    colorize(as_i("speed: "), color = "gray"),
    as_sup(sprintf("%.0f", speed))
  )
)
ft <- set_table_properties(ft, layout = "autofit")
ft
This produces cells containing italic gray text followed by a superscript number, only for rows where dist > 9.

​
Mini bar charts

minibar() renders a proportional bar as a raster image chunk: 
ft <- flextable(head(iris, n = 10))

ft <- compose(ft,
  j     = 1,
  value = as_paragraph(
    minibar(value = Sepal.Length, max = max(Sepal.Length))
  ),
  part = "body"
)
ft <- autofit(ft)
ft

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