Get filename without extension in R

Question

I have a file

ABCD.csv 

The length before the .csv is not fixed and vary to any length.

How can I extract the portion

Answer 1

You can use sub or substr

sub('\\.csv$', '', str1) 
#[1] "ABCD"

or

substr(str1, 1, nchar(str1)-4)
#[1] "ABCD"

Using the 'file_path' from @JasonV's post

sub('\\..*$', '', basename(filepath))
#[1] "ABCD"

Or

library(stringr)
str_extract(filepath,  perl('(?<=[/])([^/]+)(?=\\.[^.]+)'))
#[1] "ABCD"

data

str1 <- 'ABCD.csv'