With numeric values in a gt table, we can transform those to values of
bytes with human readable units. The fmt_bytes()
function allows for the
formatting of byte sizes to either of two common representations: (1) with
decimal units (powers of 1000, examples being "kB"
and "MB"
), and (2)
with binary units (powers of 1024, examples being "KiB"
and "MiB"
).
It is assumed the input numeric values represent the number of bytes and automatic truncation of values will occur. The numeric values will be scaled to be in the range of 1 to <1000 and then decorated with the correct unit symbol according to the standard chosen. For more control over the formatting of byte sizes, we can use the following options:
decimals: choice of the number of decimal places, option to drop trailing zeros, and a choice of the decimal symbol
digit grouping separators: options to enable/disable digit separators and provide a choice of separator symbol
pattern: option to use a text pattern for decoration of the formatted values
locale-based formatting: providing a locale ID will result in number formatting specific to the chosen locale
Usage
fmt_bytes(
data,
columns = everything(),
rows = everything(),
standard = c("decimal", "binary"),
decimals = 1,
n_sigfig = NULL,
drop_trailing_zeros = TRUE,
drop_trailing_dec_mark = TRUE,
use_seps = TRUE,
pattern = "{x}",
sep_mark = ",",
dec_mark = ".",
force_sign = FALSE,
incl_space = TRUE,
locale = NULL
)
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
).- standard
Standard used to express byte sizes
singl-kw:[decimal|binary]
// default:"decimal"
The form of expressing large byte sizes is divided between: (1) decimal units (powers of 1000; e.g.,
"kB"
and"MB"
), and (2) binary units (powers of 1024; e.g.,"KiB"
and"MiB"
).- decimals
Number of decimal places
scalar<numeric|integer>(val>=0)
// default:1
This corresponds to the exact number of decimal places to use. A value such as
2.34
can, for example, be formatted with0
decimal places and it would result in"2"
. With4
decimal places, the formatted value becomes"2.3400"
. The trailing zeros can be removed withdrop_trailing_zeros = TRUE
.- n_sigfig
Number of significant figures
scalar<numeric|integer>(val>=1)
// default:NULL
(optional
)A option to format numbers to n significant figures. By default, this is
NULL
and thus number values will be formatted according to the number of decimal places set viadecimals
. If opting to format according to the rules of significant figures,n_sigfig
must be a number greater than or equal to1
. Any values passed to thedecimals
anddrop_trailing_zeros
arguments will be ignored.- drop_trailing_zeros
Drop any trailing zeros
scalar<logical>
// default:FALSE
A logical value that allows for removal of trailing zeros (those redundant zeros after the decimal mark).
- drop_trailing_dec_mark
Drop the trailing decimal mark
scalar<logical>
// default:TRUE
A logical value that determines whether decimal marks should always appear even if there are no decimal digits to display after formatting (e.g.,
23
becomes23.
ifFALSE
). By default trailing decimal marks are not shown.- use_seps
Use digit group separators
scalar<logical>
// default:TRUE
An option to use digit group separators. The type of digit group separator is set by
sep_mark
and overridden if a locale ID is provided tolocale
. This setting isTRUE
by default.- pattern
Specification of the formatting pattern
scalar<character>
// default:"{x}"
A formatting pattern that allows for decoration of the formatted value. The formatted value is represented by the
{x}
(which can be used multiple times, if needed) and all other characters will be interpreted as string literals.- sep_mark
Separator mark for digit grouping
scalar<character>
// default:","
The string to use as a separator between groups of digits. For example, using
sep_mark = ","
with a value of1000
would result in a formatted value of"1,000"
. This argument is ignored if alocale
is supplied (i.e., is notNULL
).- dec_mark
Decimal mark
scalar<character>
// default:"."
The string to be used as the decimal mark. For example, using
dec_mark = ","
with the value0.152
would result in a formatted value of"0,152"
). This argument is ignored if alocale
is supplied (i.e., is notNULL
).- force_sign
Forcing the display of a positive sign
scalar<logical>
// default:FALSE
Should the positive sign be shown for positive numbers (effectively showing a sign for all numbers except zero)? If so, use
TRUE
for this option. The default isFALSE
, where only negative numbers will display a minus sign.- incl_space
Include a space between the value and the units
scalar<logical>
// default:TRUE
An option for whether to include a space between the value and the units. The default is to use a space character for separation.
- locale
Locale identifier
scalar<character>
// default:NULL
(optional
)An optional locale identifier that can be used for formatting values according the locale's rules. Examples include
"en"
for English (United States) and"fr"
for French (France). We can use theinfo_locales()
function as a useful reference for all of the locales that are supported. A locale ID can be also set in the initialgt()
function call (where it would be used automatically by any function with alocale
argument) but alocale
value provided here will override that global locale.
Compatibility of formatting function with data values
The fmt_bytes()
formatting function is compatible with body cells that are
of the "numeric"
or "integer"
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_bytes()
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()
:
standard
decimals
n_sigfig
drop_trailing_zeros
drop_trailing_dec_mark
use_seps
pattern
sep_mark
dec_mark
force_sign
incl_space
locale
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.
Adapting output to a specific locale
This formatting function can adapt outputs according to a provided locale
value. Examples include "en"
for English (United States) and "fr"
for
French (France). The use of a valid locale ID here means separator and
decimal marks will be correct for the given locale. Should any values be
provided in sep_mark
or dec_mark
, they will be overridden by the locale's
preferred values.
Note that a locale
value provided here will override any global locale
setting performed in gt()
's own locale
argument (it is settable there as
a value received by all other functions that have a locale
argument). As a
useful reference on which locales are supported, we can use the
info_locales()
function to view an info table.
Examples
Use a single column from the exibble
dataset and create a simple gt
table. We'll format the num
column to display as byte sizes in the decimal
standard through use of the fmt_bytes()
function.
Let's create an analogous table again by using the fmt_bytes()
function,
this time showing byte sizes as binary values by using standard = "binary"
.
See also
The vector-formatting version of this function: vec_fmt_bytes()
.
Other data formatting functions:
data_color()
,
fmt_auto()
,
fmt_bins()
,
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_url()
,
fmt()
,
sub_large_vals()
,
sub_missing()
,
sub_small_vals()
,
sub_values()
,
sub_zero()