GT.fmt

GT.fmt(self, fns, columns=None, rows=None, is_substitution=False)

Set a column format with a formatter function.

The fmt() method provides a way to execute custom formatting functionality with raw data values in a way that can consider all output contexts.

Along with the columns and rows arguments that provide some precision in targeting data cells, the fns argument allows you to define a function for manipulating the raw data.

Parameters

fns : FormatFn

A formatting function to apply to the targeted cells.

columns : SelectExpr = None

The columns to target. Can either be a single column name or a series of column names provided in a list.

rows : int | list[int] | None = None

In conjunction with columns=, we can specify which of their rows should undergo formatting. The default is all rows, resulting in all rows in columns being formatted. Alternatively, we can supply a list of row indices.

is_substitution : bool = False

Whether the formatter is a substitution. Substitutions are run last, after other formatters.

Returns

: GT

The GT object is returned. This is the same object that the method is called on so that we can facilitate method chaining.

Examples

Let’s use the exibble dataset to create a table. With the fmt() method, we’ll add a prefix ^ and a suffix $ to the row and group columns.

from great_tables import GT, exibble

(
    GT(exibble)
    .fmt(lambda x: f"^{x}$", columns=["row", "group"])
)

num	char	fctr	date	time	datetime	currency	row	group
0.1111	apricot	one	2015-01-15	13:35	2018-01-01 02:22	49.95	^row_1$	^grp_a$
2.222	banana	two	2015-02-15	14:40	2018-02-02 14:33	17.95	^row_2$	^grp_a$
33.33	coconut	three	2015-03-15	15:45	2018-03-03 03:44	1.39	^row_3$	^grp_a$
444.4	durian	four	2015-04-15	16:50	2018-04-04 15:55	65100.0	^row_4$	^grp_a$
5550.0		five	2015-05-15	17:55	2018-05-05 04:00	1325.81	^row_5$	^grp_b$
	fig	six	2015-06-15		2018-06-06 16:11	13.255	^row_6$	^grp_b$
777000.0	grapefruit	seven		19:10	2018-07-07 05:22		^row_7$	^grp_b$
8880000.0	honeydew	eight	2015-08-15	20:20		0.44	^row_8$	^grp_b$