yg_read.R

library(pdftools)
library(purrr)
res = pdftools::pdf_text("YG-Archive-DatingSocialMediaInternal-090818.pdf")
ss = strsplit(res, "\n")
names(ss) = 1:length(ss)
df = map_df(ss, function(x) {
  data.frame(txt = x, 
             row = seq_along(x),
             start = grepl("unweighted base", tolower(trimws(x))),
             stringsAsFactors = FALSE)
}, .id = "page")

start = df$txt[ df$start]
start = sub(".*base", "", start)
start = strsplit(trimws(start), " ")
start = map(start, function(x) {
  x[ x != ""]
})
ncols = sapply(start, length)

df$ncol = NA
df$ncol[ df$start] = ncols
df$ncol = zoo::na.locf(df$ncol, na.rm = FALSE)