extract portion of file name using gsub()

Question

I'm reading multiple .txt files using list.file() and file.path(). Just wanted to parse the full path names and extract the portion after the last “/” and before the “.”

Here is the structure of file path names :

"C:/Users/Alexandre/Desktop/COURS/FORMATIONS/THESE/PROJET/RESULTATS/Vessel features/Fusion/OK/SAT-DPL192C.txt"

The code I've tried

# l <- list.files(pattern = "SAT(.+)*.txt")
# f <- file.path(getwd(), c=(l))
f <- c("C:/Users/Alexandre/Desktop/COURS/FORMATIONS/THESE/PROJET/RESULTATS/Vessel features/Fusion/OK/SAT-DPL192C.txt", "C:/Users/Alexandre/Desktop/COURS/FORMATIONS/THESE/PROJET/RESULTATS/Vessel features/Fusion/OK/SAT-DPL193D.txt")
d <- lapply(f, read.delim)
names(d) <- gsub(".*/(.*)..*", "1", f)

Last string give [1] "1" "1" instead of [1] "DPL192C" "DPL193D" etc...

I've also tried the syntax like ".*/(.+)*..* for the portion to conserv with same result.

Answer 1

A . is a special character, so you need to escape it. Please, when you want to grab the captured expression, you need to use \\1, not just 1. Try this:

gsub(".*/(.*)\\..*", "\\1", f)
# [1] "SAT-DPL192C" "SAT-DPL193D"