如何在 r 中使用 pdf_convert() 设置页数 = 奇数页

Question

library(pdftools)
sapply(list, function(x)
  pdf_convert(x, format = "png", pages = NULL, filenames = NULL, dpi = 300, opw = "", upw = "", verbose = TRUE))

I know that pages = NULL means for all pages. I am having trouble how to do only odd pages. Does anyone know what I should put to do only odd pages? Thank you in advance.

Answer 1

The pages argument accepts a vector of the page numbers you want. You could make a sequence of the odd page numbers with the help of the total available in pdftools::pdf_info() .

sapply(list, function(x)
  pdf_convert(x,
              format = "png",
              pages = seq(from = 1, to = pdf_info(x)$pages, by = 2),
              filenames = NULL,
              dpi = 300,
              opw = "",
              upw = "",
              verbose = TRUE))