Extract column names character

I have a dataset dtAU where the columns names are the following:

...
"SUPG..SU.Product.Group"  
"SUPC..SU.Industry.Code" 
"SU_CAT..SU.Category"               
"FREQUENCY..Frequency" 
"TIME_PERIOD..Time.Period" 
...

I want to get the colnames as "SUPG", "SUPC", etc… so to extract only the character before the ".." and assign them as column names.

When I try this

test <- str_split(colnames(dtAU), "[..]")

I got :

List of 11
 $ : chr [1:3] "ï" "" "DATAFLOW"
 $ : chr [1:5] "SUPG" "" "SU" "Product" ...
 $ : chr [1:5] "SUPC" "" "SU" "Industry" ...
 $ : chr [1:4] "SU_CAT" "" "SU" "Category"
 $ : chr [1:3] "FREQUENCY" "" "Frequency"
 $ : chr [1:4] "TIME_PERIOD" "" "Time" "Period"
 $ : chr "OBS_VALUE"
 $ : chr [1:4] "UNIT_MEASURE" "" "Observation" "Comment"
 $ : chr [1:5] "UNIT_MULT" "" "Unit" "of" ...
 $ : chr [1:4] "OBS_STATUS" "" "Observation" "Comment"
 $ : chr [1:4] "OBS_COMMENT" "" "Observation" "Comment"

But I do not know how to retrieve as column names the first part of each character chain

>Solution :

You can do:

gsub('[..].*', '', names(dtAU)) -> names(dtAU)
gsub('\\..*', '', names(dtAU)) -> names(dtAU)

or if you want to use strsplit:

sapply(strsplit(names(dtAU), split = '\\.'), `[[`, 1) -> names(dtAU)