Format email addresses to generate 'mailto:' links

Should cells contain email addresses, the fmt_email() function can be used to make email addresses work well with email clients on the user system. This should be expressly used on columns that contain only email addresses (i.e., no email addresses as part of a larger block of text). Should you have such a column of data, there are options for how the email addresses 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).

Email addresses in data cells are trusted as email addresses. We can also provide more readable labels with the display_name argument. Supplying a single value there will show the same label for all email addresses but display names from an adjacent column could be used via a from_column() call within display_name.

Usage

fmt_email(
  data,
  columns = everything(),
  rows = everything(),
  display_name = NULL,
  as_button = FALSE,
  color = "auto",
  show_underline = "auto",
  button_fill = "auto",
  button_width = "auto",
  button_outline = "auto",
  target = NULL
)

Arguments

data

The gt table data object

obj:<gt_tbl> // required

This 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 include starts_with(), ends_with(), contains(), matches(), one_of(), num_range(), and everything().

rows

Rows to target

<row-targeting expression> // default: everything()

In conjunction with columns, we can specify which of their rows should undergo formatting. The default everything() results in all rows in columns being formatted. Alternatively, we can supply a vector of row captions within c(), a vector of row indices, or a select helper function. Examples of select helper functions include starts_with(), ends_with(), contains(), matches(), one_of(), num_range(), and everything(). We can also use expressions to filter down to the rows we need (e.g., [colname_1] > 100 & [colname_2] < 50).

display_name

Display name for the email address

scalar<character> // default: NULL (optional)

The display name is the visible 'label' to use for the email address. If NULL (the default) the address itself will serve as the display name. There are two non-NULL options: (1) a piece of static text can be used for the display name by providing a string, and (2) a function can be provided to fashion a display name from every email address.

as_button

Style email address as a button

scalar<logical> // default: FALSE

An option to style the email address as a button. By default, this is FALSE. If this option is chosen then the button_fill argument becomes usable.

color

Link color

scalar<character> // default: "auto"

The color used for the resulting email address and its underline. This is "auto" by default; this allows gt to choose an appropriate color based on various factors (such as the background button_fill when as_button is TRUE).

show_underline

Show the link underline

scalar<character>|scalar<logical> // default: "auto"

Should the email address be decorated with an underline? By default this is "auto" which means that gt will choose TRUE when as_button = FALSE and FALSE in the other case. The underline will be the same color as that set in the color option.

button_fill, button_width, button_outline

Button options

scalar<character> // default: "auto"

Options for styling an email address as a 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.

target

The 'target' anchor element attribute

scalar<character> // default: NULL

The anchor element 'target' attribute value. For a description of the 'target' attribute and its allowed values, refer to the MDN Web Docs reference on the anchor HTML element.

Value

An object of class gt_tbl.

Compatibility of formatting function with data values

The fmt_email() 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 NAs 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_email() 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():

display_name
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

Let's take ten rows from the peeps dataset and create a table of contact information with mailing addresses and email addresses. With the column that contains email addresses (email_addr), we can use fmt_email() to generate 'mailto:' links. Clicking any of these formatted email addresses should result in new message creation (depending on the OS integration with an email client).

peeps |>
  dplyr::filter(country == "AUS") |>
  dplyr::select(
    starts_with("name"),
    address, city, state_prov, postcode, country, email_addr
  ) |>
  dplyr::mutate(city = toupper(city)) |>
  gt(rowname_col = "name_family") |>
  tab_header(title = "Our Contacts in Australia") |>
  tab_stubhead(label = "Name") |>
  fmt_email(columns = email_addr) |>
  fmt_country(columns = country) |>
  cols_merge(
    columns = c(address, city, state_prov, postcode, country),
    pattern = "{1}<br>{2} {3} {4}<br>{5}"
  ) |>
  cols_merge(
    columns = c(name_family, name_given),
    pattern = "{1},<br>{2}"
  ) |>
  cols_label(
    address = "Mailing Address",
    email_addr = "Email"
  ) |>
  tab_style(
    style = cell_text(size = "x-small"),
    locations = cells_body(columns = address)
  ) |>
  opt_align_table_header(align = "left")

This image of a table was generated from the first code example in the `fmt_email()` help file.

We can further condense the table by reducing the email link to an icon. The approach we take here is the use of a fontawesome icon within the display_name argument. The icon used is "envelope" and each icon produced serves as a clickable 'mailto:' link. By adjusting one of the cols_merge() calls, we can place the icon/link next to the name of the person.

peeps |>
  dplyr::filter(country == "AUS") |>
  dplyr::select(
    starts_with("name"),
    address, city, state_prov, postcode, country, email_addr
  ) |>
  dplyr::mutate(city = toupper(city)) |>
  gt(rowname_col = "name_family") |>
  tab_header(title = "Our Contacts in Australia") |>
  fmt_email(
    columns = email_addr,
    display_name = fontawesome::fa(
      name = "envelope",
      height = "0.75em",
      fill = "gray"
    )
  ) |>
  fmt_country(columns = country) |>
  cols_merge(
    columns = c(address, city, state_prov, postcode, country),
    pattern = "{1}<br>{2} {3} {4}<br>{5}"
  ) |>
  cols_merge(
    columns = c(name_family, name_given, email_addr),
    pattern = "{1}, {2} {3}"
  ) |>
  cols_width(everything() ~ px(200)) |>
  tab_style(
    style = cell_text(size = px(11)),
    locations = cells_body(columns = address)
  ) |>
  tab_options(column_labels.hidden = TRUE) |>
  opt_align_table_header(align = "left")

This image of a table was generated from the second code example in the `fmt_email()` help file.

Another option is to display the names of the email recipients instead of the email addresses, making the display names serve as 'mailto:' links. We can do this by using the from_column() function in the display_name argument. The display names in this case are the combined given and family names, handled earlier through a dplyr::mutate() call. With some space conserved, we take the opportunity here to add in phone information for each person.

peeps |>
  dplyr::filter(country == "AUS") |>
  dplyr::mutate(name = paste(name_given, name_family)) |>
  dplyr::mutate(city = toupper(city)) |>
  dplyr::mutate(phone_number = gsub("^\\(0|\\)", "", phone_number)) |>
  dplyr::select(
    name, address, city, state_prov, postcode, country,
    email_addr, phone_number, country_code
  ) |>
  gt(rowname_col = "email_addr") |>
  tab_header(title = "Our Contacts in Australia") |>
  tab_stubhead(label = "Name") |>
  fmt_email(
    columns = email_addr,
    display_name = from_column("name"),
    color = "gray25"
  ) |>
  cols_hide(columns = name) |>
  fmt_country(columns = country) |>
  cols_merge(
    columns = c(address, city, state_prov, postcode, country),
    pattern = "{1}<br>{2} {3} {4}<br>{5}"
  ) |>
  cols_merge(
    columns = c(phone_number, country_code),
    pattern = "+{2} {1}"
  ) |>
  cols_label(
    address = "Mailing Address",
    email_addr = "Email",
    phone_number = "Phone"
  ) |>
  cols_move_to_start(columns = phone_number) |>
  cols_width(everything() ~ px(170)) |>
  tab_style(
    style = cell_text(size = px(11)),
    locations = cells_body(columns = address)
  ) |>
  cols_align(align = "left") |>
  opt_align_table_header(align = "left")

This image of a table was generated from the third code example in the `fmt_email()` help file.

Function ID

3-22

Function Introduced

In Development