Format input values to time values using one of 41 preset date styles. Input
can be in the form of POSIXt
(i.e., datetimes), the Date
type, or
character
(must be in the ISO 8601 form of YYYY-MM-DD HH:MM:SS
or
YYYY-MM-DD
).
Usage
fmt_date(
data,
columns = everything(),
rows = everything(),
date_style = "iso",
pattern = "{x}",
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
).- date_style
Predefined style for dates
scalar<character>|scalar<numeric|integer>(1<=val<=41)
--- default:"iso"
The date style to use. By default this is the short name
"iso"
which corresponds to ISO 8601 date formatting. There are 41 date styles in total and their short names can be viewed usinginfo_date_style()
.- 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.- 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_date()
formatting function is compatible with body cells that are
of the "Date"
, "POSIXt"
or "character"
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.
Formatting with the date_style
argument
We need to supply a preset date style to the date_style
argument. The date
styles are numerous and can handle localization to any supported locale. A
large segment of date styles are termed flexible date formats and this means
that their output will adapt to any locale
provided. That feature makes the
flexible date formats a better option for locales other than "en"
(the
default locale).
The following table provides a listing of all date styles and their output
values (corresponding to an input date of 2000-02-29
).
Date Style | Output | Notes | |
1 | "iso" | "2000-02-29" | ISO 8601 |
2 | "wday_month_day_year" | "Tuesday, February 29, 2000" | |
3 | "wd_m_day_year" | "Tue, Feb 29, 2000" | |
4 | "wday_day_month_year" | "Tuesday 29 February 2000" | |
5 | "month_day_year" | "February 29, 2000" | |
6 | "m_day_year" | "Feb 29, 2000" | |
7 | "day_m_year" | "29 Feb 2000" | |
8 | "day_month_year" | "29 February 2000" | |
9 | "day_month" | "29 February" | |
10 | "day_m" | "29 Feb" | |
11 | "year" | "2000" | |
12 | "month" | "February" | |
13 | "day" | "29" | |
14 | "year.mn.day" | "2000/02/29" | |
15 | "y.mn.day" | "00/02/29" | |
16 | "year_week" | "2000-W09" | |
17 | "year_quarter" | "2000-Q1" | |
18 | "yMd" | "2/29/2000" | flexible |
19 | "yMEd" | "Tue, 2/29/2000" | flexible |
20 | "yMMM" | "Feb 2000" | flexible |
21 | "yMMMM" | "February 2000" | flexible |
22 | "yMMMd" | "Feb 29, 2000" | flexible |
23 | "yMMMEd" | "Tue, Feb 29, 2000" | flexible |
24 | "GyMd" | "2/29/2000 A" | flexible |
25 | "GyMMMd" | "Feb 29, 2000 AD" | flexible |
26 | "GyMMMEd" | "Tue, Feb 29, 2000 AD" | flexible |
27 | "yM" | "2/2000" | flexible |
28 | "Md" | "2/29" | flexible |
29 | "MEd" | "Tue, 2/29" | flexible |
30 | "MMMd" | "Feb 29" | flexible |
31 | "MMMEd" | "Tue, Feb 29" | flexible |
32 | "MMMMd" | "February 29" | flexible |
33 | "GyMMM" | "Feb 2000 AD" | flexible |
34 | "yQQQ" | "Q1 2000" | flexible |
35 | "yQQQQ" | "1st quarter 2000" | flexible |
36 | "Gy" | "2000 AD" | flexible |
37 | "y" | "2000" | flexible |
38 | "M" | "2" | flexible |
39 | "MMM" | "Feb" | flexible |
40 | "d" | "29" | flexible |
41 | "Ed" | "29 Tue" | flexible |
We can use the info_date_style()
function within the console to view a
similar table of date styles with example output.
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). 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
Let's use the exibble
dataset to create a simple, two-column gt table
(keeping only the date
and time
columns). With the fmt_date()
function,
we'll format the date
column to display dates formatted with the
"month_day_year"
date style.
exibble |>
dplyr::select(date, time) |>
gt() |>
fmt_date(
columns = date,
date_style = "month_day_year"
)
Again using the exibble
dataset, let's format the date
column to have
mixed date formats, where dates after April 1st will be different than the
others because of the expressions used in the rows
argument. This will
involve two calls of fmt_date()
with different statements provided for
rows
. In the first call (dates after the 1st of April) the date style
"m_day_year"
is used; for the second call, "day_m_year"
is the named
date style supplied to date_style
.
exibble |>
dplyr::select(date, time) |>
gt() |>
fmt_date(
columns = date,
rows = as.Date(date) > as.Date("2015-04-01"),
date_style = "m_day_year"
) |>
fmt_date(
columns = date,
rows = as.Date(date) <= as.Date("2015-04-01"),
date_style = "day_m_year"
)
Use the exibble
dataset to create a single-column gt table (with only
the date
column). Format the date values using the "yMMMEd"
date style
(which is one of the 'flexible' styles). Also, we'll set the locale to "nl"
to get the dates in Dutch.
See also
The vector-formatting version of this function: vec_fmt_date()
.
Other data formatting functions:
data_color()
,
fmt_auto()
,
fmt_bins()
,
fmt_bytes()
,
fmt_currency()
,
fmt_datetime()
,
fmt_duration()
,
fmt_engineering()
,
fmt_flag()
,
fmt_fraction()
,
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_url()
,
fmt()
,
sub_large_vals()
,
sub_missing()
,
sub_small_vals()
,
sub_values()
,
sub_zero()