How to extract separate data from an out-of-format string

Question

When extracting data from a pdf in R, extracting text line by line, I have the following situation. A string of interest that comes with three information separated by long spaces, as exemplified below

a <- "WDFG V/AA 8952                              123546514            sdfasfasfa"

need to extract only "WDFG V/AA 8952"

Since there are many pdfs, you would need a method to insert a looping and scale the process.

Answer 1

I believe this regular expression solves the problem.

The data are these:

a <- c("João Fernando Freitas                             123546514            sdfasfasfa",
       "WDFG V/AA 8952                              123546514            sdfasfasfa")

And the regular expression.

b <- sub("(^[[:alnum:]]*| ) {2,}([[:alnum:]]| )*$", "\\1", a)
b <- trimws(b)
b
#[1] "João Fernando Freitas" "WDFG V/AA 8952" 

If you want to insert a loop, you might want to put the above code in a function.

extraiNome <- function(x){
  b <- sub("(^[[:alnum:]]*| ) {2,}([[:alnum:]]| )*$", "\\1", x)
  trimws(b)
}

extraiNome(a)
#[1] "João Fernando Freitas" "WDFG V/AA 8952"