fmt_units {gt} | R Documentation |
Format measurement units
Description
fmt_units()
lets you better format measurement units in the table body.
These must conform to gt's specialized units notation (e.g.,
"J Hz^-1 mol^-1"
can be used to generate units for the
molar Planck constant) for the best conversion. The notation here provides
several conveniences for defining units, so as long as the values to be
formatted conform to this syntax, you'll obtain nicely-formatted units no
matter what the table output format might be (i.e., HTML, LaTeX, RTF, etc.).
Details pertaining to the units notation can be found in the section entitled
How to use gt's units notation.
Usage
fmt_units(data, columns = everything(), rows = everything())
Arguments
data |
The gt table data object
This is the gt table object that is commonly created through use of the
|
columns |
Columns to target
Can either be a series of column names provided in |
rows |
Rows to target
In conjunction with |
Value
An object of class gt_tbl
.
How to use gt's units notation
The units notation involves a shorthand of writing units that feels familiar and is fine-tuned for the task at hand. Each unit is treated as a separate entity (parentheses and other symbols included) and the addition of subscript text and exponents is flexible and relatively easy to formulate. This is all best shown with examples:
-
"m/s"
and"m / s"
both render as"m/s"
-
"m s^-1"
will appear with the"-1"
exponent intact -
"m /s"
gives the same result, as"/<unit>"
is equivalent to"<unit>^-1"
-
"E_h"
will render an"E"
with the"h"
subscript -
"t_i^2.5"
provides at
with an"i"
subscript and a"2.5"
exponent -
"m[_0^2]"
will use overstriking to set both scripts vertically -
"g/L %C6H12O6%"
uses a chemical formula (enclosed in a pair of"%"
characters) as a unit partial, and the formula will render correctly with subscripted numbers Common units that are difficult to write using ASCII text may be implicitly converted to the correct characters (e.g., the
"u"
in"ug"
,"um"
,"uL"
, and"umol"
will be converted to the Greek mu symbol;"degC"
and"degF"
will render a degree sign before the temperature unit)We can transform shorthand symbol/unit names enclosed in
":"
(e.g.,":angstrom:"
,":ohm:"
, etc.) into proper symbolsGreek letters can added by enclosing the letter name in
":"
; you can use lowercase letters (e.g.,":beta:"
,":sigma:"
, etc.) and uppercase letters too (e.g.,":Alpha:"
,":Zeta:"
, etc.)The components of a unit (unit name, subscript, and exponent) can be fully or partially italicized/emboldened by surrounding text with
"*"
or"**"
Examples
Let's use the illness
dataset and create a new gt table. The units
column contains character values in gt's specialized units notation
(e.g., "x10^9 / L"
) so the fmt_units()
function was used to better format
those units.
illness |> gt() |> fmt_units(columns = units) |> sub_missing(columns = -starts_with("norm")) |> sub_missing(columns = c(starts_with("norm"), units), missing_text = "") |> sub_large_vals(rows = test == "MYO", threshold = 1200) |> fmt_number( decimals = 2, drop_trailing_zeros = TRUE ) |> tab_header(title = "Laboratory Findings for the YF Patient") |> tab_spanner(label = "Day", columns = starts_with("day")) |> cols_label_with(fn = ~ gsub("day_", "", .)) |> cols_merge_range(col_begin = norm_l, col_end = norm_u) |> cols_label( starts_with("norm") ~ "Normal Range", test ~ "Test", units ~ "Units" ) |> cols_width( starts_with("day") ~ px(80), everything() ~ px(120) ) |> tab_style( style = cell_text(align = "center"), locations = cells_column_labels(columns = starts_with("day")) ) |> tab_style( style = cell_fill(color = "aliceblue"), locations = cells_body(columns = c(test, units)) ) |> opt_vertical_padding(scale = 0.4) |> opt_align_table_header(align = "left") |> tab_options(heading.padding = px(10))

The constants
dataset contains values for hundreds of fundamental
physical constants. We'll take a subset of values that have some molar basis
and generate a gt table from that. Like the illness
dataset, this one
has a units
column so, again, the fmt_units()
function will be used to
format those units. Here, the preference for typesetting measurement units is
to have positive and negative exponents (e.g., not "<unit_1> / <unit_2>"
but rather "<unit_1> <unit_2>^-1"
).
constants |> dplyr::filter(grepl("molar", name)) |> gt() |> cols_hide(columns = c(uncert, starts_with("sf"))) |> fmt_units(columns = units) |> fmt_scientific(columns = value, decimals = 3) |> tab_header(title = "Physical Constants Having a Molar Basis") |> tab_options(column_labels.hidden = TRUE)

Function ID
3-19
Function Introduced
v0.10.0
(October 7, 2023)
See Also
Other data formatting functions:
data_color()
,
fmt()
,
fmt_auto()
,
fmt_bins()
,
fmt_bytes()
,
fmt_chem()
,
fmt_country()
,
fmt_currency()
,
fmt_date()
,
fmt_datetime()
,
fmt_duration()
,
fmt_email()
,
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_tf()
,
fmt_time()
,
fmt_url()
,
sub_large_vals()
,
sub_missing()
,
sub_small_vals()
,
sub_values()
,
sub_zero()