Should cells contain URLs, the fmt_url()
function can be used to make them
navigable links. This should be expressly used on columns that contain only
URL text (i.e., no URLs as part of a larger block of text). Should you have
such a column of data, there are options for how the links should be styled.
They can be of the conventional style (with underlines and text coloring that
sets it apart from other text), or, they can appear to be button-like (with
a surrounding box that can be filled with a color of your choosing).
URLs in data cells are detected in two ways. The first is using the simple
Markdown notation for URLs of the form: [label](URL)
. The second assumes
that the text is the URL. In the latter case the URL is also used as the
label but there is the option to use the label
argument to modify that
text.
Usage
fmt_url(
data,
columns = everything(),
rows = everything(),
label = NULL,
as_button = FALSE,
color = "auto",
show_underline = "auto",
button_fill = "auto",
button_width = "auto",
button_outline = "auto"
)
Arguments
- data
The gt table data object
obj:<gt_tbl>
// requiredThis is the gt table object that is commonly created through use of the
gt()
function.- columns
Columns to target
<column-targeting expression>
// default:everything()
Can either be a series of column names provided in
c()
, a vector of column indices, or a select helper function. Examples of select helper functions includestarts_with()
,ends_with()
,contains()
,matches()
,one_of()
,num_range()
, andeverything()
.- rows
Rows to target
<row-targeting expression>
// default:everything()
In conjunction with
columns
, we can specify which of their rows should undergo formatting. The defaulteverything()
results in all rows incolumns
being formatted. Alternatively, we can supply a vector of row captions withinc()
, a vector of row indices, or a select helper function. Examples of select helper functions includestarts_with()
,ends_with()
,contains()
,matches()
,one_of()
,num_range()
, andeverything()
. We can also use expressions to filter down to the rows we need (e.g.,[colname_1] > 100 & [colname_2] < 50
).- label
Link label
scalar<character>
// default:NULL
(optional
)The visible 'label' to use for the link. If
NULL
(the default) the URL will serve as the label. There are two non-NULL
options: (1) a static text can be used for the label by providing a string, and (2) a function can be provided to fashion a label from every URL.- as_button
Style link as a button
scalar<logical>
// default:FALSE
An option to style the link as a button. By default, this is
FALSE
. If this option is chosen then thebutton_fill
argument becomes usable.- color
Link color
scalar<character>
// default:"auto"
The color used for the resulting link and its underline. This is
"auto"
by default; this allows gt to choose an appropriate color based on various factors (such as the backgroundbutton_fill
whenas_button
isTRUE
).- show_underline
Show the link underline
scalar<character>|scalar<logical>
// default:"auto"
Should the link be decorated with an underline? By default this is
"auto"
which means that gt will chooseTRUE
whenas_button = FALSE
andFALSE
in the other case. The link underline will be the same color as that set in thecolor
option.- button_fill, button_width, button_outline
Button options
scalar<character>
// default:"auto"
Options for styling a link-as-button (and only applies if
as_button = TRUE
). All of these options are by default set to"auto"
, allowing gt to choose appropriate fill, width, and outline values.
Compatibility of formatting function with data values
The fmt_url()
formatting function is compatible with body cells that are
of the "character"
or "factor"
types. Any other types of body cells are
ignored during formatting. This is to say that cells of incompatible data
types may be targeted, but there will be no attempt to format them.
Targeting cells with columns
and rows
Targeting of values is done through columns
and additionally by rows
(if
nothing is provided for rows
then entire columns are selected). The
columns
argument allows us to target a subset of cells contained in the
resolved columns. We say resolved because aside from declaring column names
in c()
(with bare column names or names in quotes) we can use
tidyselect-style expressions. This can be as basic as supplying a select
helper like starts_with()
, or, providing a more complex incantation like
where(~ is.numeric(.x) && max(.x, na.rm = TRUE) > 1E6)
which targets numeric columns that have a maximum value greater than
1,000,000 (excluding any NA
s from consideration).
By default all columns and rows are selected (with the everything()
defaults). Cell values that are incompatible with a given formatting function
will be skipped over, like character
values and numeric fmt_*()
functions. So it's safe to select all columns with a particular formatting
function (only those values that can be formatted will be formatted), but,
you may not want that. One strategy is to format the bulk of cell values with
one formatting function and then constrain the columns for later passes with
other types of formatting (the last formatting done to a cell is what you get
in the final output).
Once the columns are targeted, we may also target the rows
within those
columns. This can be done in a variety of ways. If a stub is present, then we
potentially have row identifiers. Those can be used much like column names in
the columns
-targeting scenario. We can use simpler tidyselect-style
expressions (the select helpers should work well here) and we can use quoted
row identifiers in c()
. It's also possible to use row indices (e.g.,
c(3, 5, 6)
) though these index values must correspond to the row numbers of
the input data (the indices won't necessarily match those of rearranged rows
if row groups are present). One more type of expression is possible, an
expression that takes column values (can involve any of the available columns
in the table) and returns a logical vector. This is nice if you want to base
formatting on values in the column or another column, or, you'd like to use a
more complex predicate expression.
Compatibility of arguments with the from_column()
helper function
The from_column()
helper function can be used with certain arguments of
fmt_url()
to obtain varying parameter values from a specified column within
the table. This means that each row could be formatted a little bit
differently. These arguments provide support for from_column()
:
label
as_button
color
show_underline
button_fill
button_width
button_outline
Please note that for each of the aforementioned arguments, a from_column()
call needs to reference a column that has data of the correct type (this is
different for each argument). Additional columns for parameter values can be
generated with the cols_add()
function (if not already present). Columns
that contain parameter data can also be hidden from final display with
cols_hide()
. Finally, there is no limitation to how many arguments the
from_column()
helper is applied so long as the arguments belong to this
closed set.
Examples
Using a portion of the towny
dataset, let's create a gt table. We can
use the fmt_url()
function on the website
column to generate navigable
links to websites. By default the links are underlined and the color will be
chosen for you (it's dark cyan).
towny |>
dplyr::filter(csd_type == "city") |>
dplyr::arrange(desc(population_2021)) |>
dplyr::select(name, website, population_2021) |>
dplyr::slice_head(n = 10) |>
gt() |>
tab_header(
title = md("The 10 Largest Municipalities in `towny`"),
subtitle = "Population values taken from the 2021 census."
) |>
fmt_integer() |>
fmt_url(columns = website) |>
cols_label(
name = "Name",
website = "Site",
population_2021 = "Population"
)
Let's try something else. We can set a static text label for the link with
the label
argument (and we'll use the word "site"
for this). The link
underline is removable with show_underline = FALSE
. With this change, it
seems sensible to merge the link to the "name"
column and enclose the link
text in parentheses (the cols_merge()
function handles all that).
towny |>
dplyr::filter(csd_type == "city") |>
dplyr::arrange(desc(population_2021)) |>
dplyr::select(name, website, population_2021) |>
dplyr::slice_head(n = 10) |>
gt() |>
tab_header(
title = md("The 10 Largest Municipalities in `towny`"),
subtitle = "Population values taken from the 2021 census."
) |>
fmt_integer() |>
fmt_url(
columns = website,
label = "site",
show_underline = FALSE
) |>
cols_merge(
columns = c(name, website),
pattern = "{1} ({2})"
) |>
cols_label(
name = "Name",
population_2021 = "Population"
)
The fmt_url()
function allows for the styling of links as 'buttons'. This
is as easy as setting as_button = TRUE
. Doing that unlocks the ability to
set a button_fill
color. This color can automatically selected by gt
(this is the default) but here we're using "steelblue"
. The label
argument also accepts a function! We can choose to adapt the label text from
the URLs by eliminating any leading "https://"
or "www."
parts.
towny |>
dplyr::filter(csd_type == "city") |>
dplyr::arrange(desc(population_2021)) |>
dplyr::select(name, website, population_2021) |>
dplyr::slice_head(n = 10) |>
dplyr::mutate(ranking = dplyr::row_number()) |>
gt(rowname_col = "ranking") |>
tab_header(
title = md("The 10 Largest Municipalities in `towny`"),
subtitle = "Population values taken from the 2021 census."
) |>
fmt_integer() |>
fmt_url(
columns = website,
label = function(x) gsub("https://|www.", "", x),
as_button = TRUE,
button_fill = "steelblue",
button_width = px(150)
) |>
cols_move_to_end(columns = website) |>
cols_align(align = "center", columns = website) |>
cols_width(
ranking ~ px(40),
website ~ px(200)
) |>
tab_options(column_labels.hidden = TRUE) |>
tab_style(
style = cell_text(weight = "bold"),
locations = cells_stub()
) %>%
opt_vertical_padding(scale = 0.75)
It's perhaps inevitable that you'll come across missing values in your column
of URLs. The fmt_url()
function will preserve input NA
values, allowing
you to handle them with sub_missing()
. Here's an example of that.
towny |>
dplyr::arrange(population_2021) |>
dplyr::select(name, website, population_2021) |>
dplyr::slice_head(n = 10) |>
gt() |>
tab_header(
title = md("The 10 Smallest Municipalities in `towny`"),
subtitle = "Population values taken from the 2021 census."
) |>
fmt_integer() |>
fmt_url(columns = website) |>
cols_label(
name = "Name",
website = "Site",
population_2021 = "Population"
) |>
sub_missing()
See also
Other data formatting functions:
data_color()
,
fmt_auto()
,
fmt_bins()
,
fmt_bytes()
,
fmt_currency()
,
fmt_datetime()
,
fmt_date()
,
fmt_duration()
,
fmt_engineering()
,
fmt_flag()
,
fmt_fraction()
,
fmt_icon()
,
fmt_image()
,
fmt_index()
,
fmt_integer()
,
fmt_markdown()
,
fmt_number()
,
fmt_partsper()
,
fmt_passthrough()
,
fmt_percent()
,
fmt_roman()
,
fmt_scientific()
,
fmt_spelled_num()
,
fmt_time()
,
fmt_units()
,
fmt()
,
sub_large_vals()
,
sub_missing()
,
sub_small_vals()
,
sub_values()
,
sub_zero()