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

Loading the library needed :

> library(stringr)

Extracting all the matches from the regex:

> str_match("ABCD.csv", "(.*)\\..*$")
     [,1]       [,2]  
[1,] "ABCD.csv" "ABCD"

Returning only the second part of the result, which corresponds to the group matching the file name:

> str_match("ABCD.csv", "(.*)\\..*$")[,2]
[1] "ABCD"

EDIT for @U-10-Forward:

It is basically the same principle as the other answer. Just that I found this solution more robust.

Regex wise it means:

• () = group

• .* = any single character except the newline character any number of time

• // is escape notation, thus //. means literally "."

• .* = any characters any number of time again

• $ means should be at the end of the input string

The logic is then that it will return the group preceding a "." followed by a group of characters at the end of the string (which equals the file extension in this case).