Example produces NAs

[dcaud]

This:

# install.packages("pdfsearch")
library(pdfsearch)
file <- system.file('pdf', '1610.00147.pdf', package = 'pdfsearch')

result <- keyword_search(file, 
                         keyword = c('measurement', 'error'),
                         path = TRUE)

head(result$line_text, n = 2)

Results in:

[[1]]
[1] "Reiter, Maria DeYoreo∗ arXiv:1610.00147v1 [stat.ME] 1 Oct 2016 Abstract Often in surveys, key items are subject to measurement errors. "

[[2]]
[1] "In NA NA dividuals with high quality measurements of the error-prone survey items. "

Notice the NA's in the second item.