Making a toy package on R, unable to use the other functions in the R file

Question

I am trying to create my own R-package as an exercise. I have followed the online tutorials by Hillary Parker and have managed to get something going.

The package I am trying to make takes a csv file, and prints the head() and tail() of the dataset. And then I wrote another function that would print the head() and tail() value in a text file.

ExercisePkg <- function(.csv) {

  csv <- read.csv(.csv)

  headValue <- head(csv)
  print("The head of the dataset is:")
  print(headValue)

  tailValue <- tail(csv)
  print("The tail of the dataset is:")
  print(tailValue)

  return(list(headValue, tailValue))
}

My next function is to print the headValue and the tailValue into a text file. For that I use sink() and modify the ExercisePkg as follows:

ExercisePkgTxt <- function(.csv) {

  sink('Report.txt')
  csv <- read.csv(.csv)

  headValue <- head(csv)
  print("The head of the dataset is:")
  print(headValue)

  tailValue <- tail(csv)
  print("The tail of the dataset is:")
  print(tailValue)

  return(list(headValue, tailValue))
  sink('Report.txt', append=TRUE)
}

I have both this functions in the code.R file as:

#' Function to see head and tail of a csv file
#'
#' Function is cool.
#' @param Do you love data? Defaults to TRUE
#' @keywords csv, data, head, tail,text.
#' @export ExercisePkg(),ExercisePkgTxt()
#' @examples no examples
#' ExercisePkg()
#' ExercisePKgTxt()

ExercisePkg <- function(.csv) {

      csv <- read.csv(.csv)

      headValue <- head(csv)
      print("The head of the dataset is:")
      print(headValue)

      tailValue <- tail(csv)
      print("The tail of the dataset is:")
      print(tailValue)

      return(list(headValue, tailValue))
    }

    ExercisePkgTxt <- function(.csv) {

      sink('Report.txt')
      csv <- read.csv(.csv)

      headValue <- head(csv)
      print("The head of the dataset is:")
      print(headValue)

      tailValue <- tail(csv)
      print("The tail of the dataset is:")
      print(tailValue)

      return(list(headValue, tailValue))
      sink('Report.txt', append=TRUE)
    }

It is kept inside the /path/ToyPackage/R/code.R.

After I installed the package. I tried testing it.

The ExercisePkg("/path/dataset.csv") worked like a charm.

But the ExercisePkgTxt("/path/dataset.csv") gave an error like Error: could not find function "ExercisePkgTxt"

I tried putting both the functions in separate R file (code.R for ExercisePkg() and code1.R for ExercisePkgTxt()) and rebuild the package. But the problem did not go away.

When I try running document() I get the following:

>document()
Updating ToyPackage documentation
Loading ToyPackage
Writing NAMESPACE
Writing ExercisePkg.Rd
>

The NAMESPACE file looks like this:

# Generated by roxygen2: do not edit by hand

export("ExercisePkg(),ExercisePkgTxt()")

And when I try to install the package by install("ToyPackage"). I get the following error:

* installing *source* package 'ToyPackage' ...
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
*** arch - i386
Error in namespaceExport(ns, exports) : 
  undefined exports: ExercisePkg(),ExercisePkgTxt()
Error: loading failed
Execution halted
*** arch - x64
Error in namespaceExport(ns, exports) : 
  undefined exports:  ExercisePkg(),ExercisePkgTxt()
Error: loading failed
Execution halted
ERROR: loading failed for 'i386', 'x64'
* removing 'C:/Users/user/Documents/R/win-library/3.3/ToyPackage'
Error: Command failed (1)

What am I doing wrong?

Please do not give me a whole new code altogether, just suggest some changes, if any.

Thanks.

How does your NAMESPACE file look like? Did you load the package after building it? You are aware that code in a function after a call to `return` is never executed? — Roland, Sep 29 '16 at 10:43
Creating pkgs is not a trivial task and you're first attempt is very commendable! Definitely poke at what Roland suggested and I'd definitely read (or at least skim through) [R Packages](http://r-pkgs.had.co.nz) by Hadley before proceeding much further. I think you'll find it _much_ easier to use the `roxygen` and `devtools` to streamline pkg development. — hrbrmstr, Sep 29 '16 at 10:50
@Roland I added the namespace in the question. It looks like it only takes the first function into account. How do I go about this? — Pragyaditya Das, Sep 29 '16 at 10:57
@Roland, I added more information to the question. Please have a look. — Pragyaditya Das, Sep 29 '16 at 11:31
@hrbrmstr, I added more information to the question. Please have a look. — Pragyaditya Das, Sep 29 '16 at 11:31

Hong Ooi · Accepted Answer · 2016-09-29T11:08:45.510

1

Since you're using Roxygen and devtools, you need to do the following:

Include a #' @export directive for every function you want to export from your package
Run document() before building/installing the package, to ensure the NAMESPACE file is updated.

edited Sep 29 '16 at 11:08

answered Sep 29 '16 at 11:02

Hong Ooi

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Even after I ran `document()`, the NAMESPACE remained the same as I have provided in the question. – Pragyaditya Das Sep 29 '16 at 11:05
1

You also need to include `#' @export` directives for all the functions you want to export. – Hong Ooi Sep 29 '16 at 11:07
Like `#' @export ExercisePkg(), ExercisePkgTxt() ?` or `#' @export ExercisePkg(.csv), ExercisePkgTxt(.csv) ?` – Pragyaditya Das Sep 29 '16 at 11:11
I made some changes in the code as suggested by you. Please have a look at the modifications of the question. – Pragyaditya Das Sep 29 '16 at 11:32
1

I did some playing around and it worked. Please make your comment a part of the answer and I will mark it as accepted. :) – Pragyaditya Das Sep 29 '16 at 11:42

Making a toy package on R, unable to use the other functions in the R file

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