I have a large R script I am trying to source in a LaTex document and then reference output from specific dataframes created in the source code in text in a LaTex paragraph.

When I compile the PDF I receive an error message that object num_stations is not found.

A small example:


You can type R commands in your \LaTeX{} document and they will be properly run and the output printed in the document.

opts_chunk$set(echo=F,message=F, warnings=F)

#need com_dredge, table 2.1 and num_stations from this source code
source(file="S:/Adv/Scallop Central/2018 Scallop RSA/Industry Report/Industry Report.R")

#num_stations dataframe needed for text below
This is a value $\Sexpr{num_stations$Number}$.


When I run the code chunk I dont think the source line is working. I have read a couple different options: 1. The source file needs to be in the same folder as the knitr file. I tried this an got the error message cannot open the connection. 2. Type out the path in the source code.
I also tried that and got the same message. 3. Use

  opts_knit$set(root.dir = '/Users/username/path_to_project').

I also tried this in the code chunk in the latex file and got the same message.

I would appreciate any help.

  • Are you looking for verbatim environment?
    – Sigur
    Feb 13, 2019 at 21:09
  • I'm guessing this isn't the problem, but spaces in path names are occasionally problematic. Could you try a directory without any spaces? Could you also add a minimal R file that reproduces the problem?
    – Teepeemm
    Feb 13, 2019 at 21:21
  • I wasnt sure how to provide a R file that reproduces the example because its a source file. Do you have any suggestions? I did try a directory with no spaces and didnt have any luck.
    – user41509
    Feb 14, 2019 at 14:23

1 Answer 1


foo.R (in the working directory):

# ---- test  ----

bah <- data.frame(a=c(1,2,3),b=c(4,5,6))

test.Rnw (in the same working directory):

<<mychuck, cache=F,echo=F>>=
kable(bah, caption="my data", booktabs = TRUE)
The variable \verb|bah$a| is \Sexpr{combine_words(bah$a)}.

To compile the above file use Rstudio or see How to build Knitr document from the command line.


  • When I run your example I get the following errors: Line 5 Missing $ inserted, Line 12 Missing $ inserted and the PDF doesnt compile. Also, my question was related to getting values from a dataframe into test using $\Sexpr{num_stations$Number}$.
    – user41509
    Feb 14, 2019 at 14:34
  • @user41509 Sorry, I wrote wrongly test.tex instead of test.Rnw, but it should be a obvious mistake if you are used to compile knitr files. If not, I suggest use Rstudio. Once you loaded the chunk of the external script is irrelevant if you call the whole data frame in a table of another chunk or only a variable in a \Sexpr{}. It should work anyway. See my updated answer.
    – Fran
    Feb 14, 2019 at 17:44
  • Thank you - I was able to get my source code to work with my document. This is my first time using Latex so am not familiar with the different ways to compile files. I am using R studio.
    – user41509
    Mar 1, 2019 at 16:28

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