Create multi level headers

This vignette introduces how to create multi level headers.

library(ftExtra)
#> Registered S3 method overwritten by 'ftExtra':
#>   method                  from     
#>   as_flextable.data.frame flextable

Prepare flextable

ft <- iris[1:2, ] %>% flextable()
ft

Sepal.Length	Sepal.Width	Petal.Length	Petal.Width	Species
5.1	3.5	1.4	0.2	setosa
4.9	3.0	1.4	0.2	setosa

Split headers

The split_header() function generates multi-level headers by separating original headers (row names) by delimiters.

ft %>% split_header()

Sepal	Sepal	Petal	Petal	Species
Length	Width	Length	Width
5.1	3.5	1.4	0.2	setosa
4.9	3.0	1.4	0.2	setosa

The sep argument defines delimiters by regular expression. The default delimiters are . and _. Let’s see what happens when seop = "e"

ft %>% split_header(sep = "e")

S	S	P	P	Sp
pal.L	pal.Width	tal.L	tal.Width	ci
ngth		ngth		s
5.1	3.5	1.4	0.2	setosa
4.9	3.0	1.4	0.2	setosa

Span headers

The span_header() function also generates multi-level headers. Unlike the split_header() function, the span_header() function merges adjacent headers if they have same values.

ft %>% span_header()

Sepal		Petal		Species
Length	Width	Length	Width
5.1	3.5	1.4	0.2	setosa
4.9	3.0	1.4	0.2	setosa