Extract Text from Two-Column PDF with R
There is a much easier way to do this using tabulizer::extract_text(file)
function.
It works with PDF text contained in a single column and PDF text contained in 2+ columns. Yes, it's that simple!
I'd the same problem. What I did was to get the most frequent space values for each of my pdfs pages and stored it into a Vector. Then I sliced it using that value.
library(pdftools)
src <- ""
trim <- function (x) gsub("^\\s+|\\s+$", "", x)
QTD_COLUMNS <- 2
read_text <- function(text) {
result <- ''
#Get all index of " " from page.
lstops <- gregexpr(pattern =" ",text)
#Puts the index of the most frequents ' ' in a vector.
stops <- as.integer(names(sort(table(unlist(lstops)),decreasing=TRUE)[1:2]))
#Slice based in the specified number of colums (this can be improved)
for(i in seq(1, QTD_COLUMNS, by=1))
{
temp_result <- sapply(text, function(x){
start <- 1
stop <-stops[i]
if(i > 1)
start <- stops[i-1] + 1
if(i == QTD_COLUMNS)#last column, read until end.
stop <- nchar(x)+1
substr(x, start=start, stop=stop)
}, USE.NAMES=FALSE)
temp_result <- trim(temp_result)
result <- append(result, temp_result)
}
result
}
txt <- pdf_text(src)
result <- ''
for (i in 1:length(txt)) {
page <- txt[i]
t1 <- unlist(strsplit(page, "\n"))
maxSize <- max(nchar(t1))
t1 <- paste0(t1,strrep(" ", maxSize-nchar(t1)))
result = append(result,read_text(t1))
}
result