I've thrown together a bunch of my utility functions into a package. However, I can't seem to access them after I've installed the package. I get errors of the form Error: object 'function_name' not found
Building the package, there are no error messages
Installing the package from source, there are no error messages
Loading the package, there are no error messages (library() nor require())
The package documentation is accessible once loaded
I'm using roxygen2 to generate documentation and the namespace
Any thoughts?
Do you use a NAMESPACE and forgot to add the object in question?
If you're using roxygen2, have you remembered to add #' #export function_name to the functions you want included in the namespace?
If the function name is not exported, you may need to use ":::"
pkgname:::function_name
I believe that CRAN now requires a NAMESPACE, and I think R 2.14.x may even require them.
The same problem for me, you need to change NAMESPACE file. sometime NAMESPACE's content looks like this:
# Generated by roxygen2: do not edit by hand
But you need to change it by hand, like this:
# Generated by roxygen2: do not edit by hand
export("function_name1", "function_name2")
OR use exportPattern("^[^\\.]") to export all function.
Related
Currently I have in my package DESCRIPTION, a dependency on dbplyr:
Imports:
dbplyr,
dplyr
dbplyr is useful almost solely because of the S3 methods it defines: https://github.com/tidyverse/dbplyr/blob/main/NAMESPACE. The actual functions you call to use dbplyr are almost entirely from dplyr.
By putting dbplyr in my Imports, it should automatically get loaded, but not attached, which should be enough to register its S3 methods: https://r-pkgs.org/dependencies-mindset-background.html#sec-dependencies-attach-vs-load.
This seems to work fine, but whenever I R CMD check, it tells me:
N checking dependencies in R code (10.8s)
Namespace in Imports field not imported from: ‘dbplyr’
All declared Imports should be used.
Firstly, why does R CMD check even check this, considering that it often makes sense to load packages without importing them. Secondly, how am I supposed to satisfy R CMD check without loading things into my namespace that I don't want or need?
I am pretty sure two of your assumptions are false.
First, putting Imports: dbplyr into your DESCRIPTION file won't load it, so its methods won't be loaded from that alone. Basically the Imports field in the DESCRIPTION file just guarantees that dbplyr is available to be loaded when requested. If you import something via the NAMESPACE file, that will cause it to be loaded. If you evaluate dbplyr::something that will cause it to be loaded. Executing loadNamespace("dbplyr") is another way, and there are a few others. You may also load some other package that loads it.
Second, I think you have misinterpreted the error message. It isn't saying that you loaded it without importing it (though it would complain about that too), it is saying that it can't detect any use of it in your package, so maybe it shouldn't be a requirement for installing your package.
Unfortunately, the code to detect uses is fallible, so it sometimes misses uses. Examples I've heard about are:
if the package is only used in the default value for a function argument. This has been fixed in R-devel.
if the package is only used during the build to construct some object, e.g. code like someclass <- R6::R6Class( ... ) needs R6, but the check code won't see it because it looks at someclass, not at the source code that created it.
if the use of the package is hidden by specifying the name of the package in a character variable.
if the need for the package is indirect, e.g. you need to use ggplot2::geom_hex. That needs the hexbin package, but ggplot2 only declares it as "Suggested".
These examples come from this discussion: https://github.com/hadley/r-pkgs/issues/828#issuecomment-1421353457 .
The recommended workaround there is to create an object that refers to the imported package explicitly, e.g. putting the line
dummy_r6 <- function() R6::R6Class
into your package is enough to suppress the note without actually loading R6. (It will be loaded if you ever call this function.)
However, your requirement is stronger: you do need to make sure dbplyr is loaded if you want its methods to be used. I'd put something in your .onLoad() function that triggers the load. For example,
.onLoad <- function(lib, pkg) {
# Make sure the dbplyr methods are loaded
loadNamespace("dbplyr")
}
EDITED TO ADD: As pointed out in the comments, there's a bug in the check code that means it won't detect this as being a use of dbplyr. You really need to do both things, e.g.
.onLoad <- function(lib, pkg) {
# Make sure the dbplyr methods are loaded
loadNamespace("dbplyr")
# Work around bug in code checking in R 4.2.2 for use of packages
dummy <- function() dbplyr::across_apply_fns
}
The function used in the dummy construction is arbitrary; it probably doesn't even need to exist, but I chose one that does.
I am receiving an error [could not find function "str_trim"] when I run check() on an R package I am developing. I have since added two things:
1) In DESCRIPTION
Imports: stringr
2) In NAMESPACE
importFrom(stringr,str_trim)
However, when I then run install() and document(), then the line in NAMESPACE is removed. Then, when I again run check(), I receive the original error.
Why is this line being removed? Should I try a different approach, and if so, what kind of approach? Thank you!
It seems you are doing package development "the Hadley way".
Hadley wants you to use roxygen (i.e. the roxygen2 package but that should be automatic if you use his 'devtools').
Then, the roxygen "magic" is used to auto-write your NAMESPACE file... and so also destroys things you've put there.
You must add #importFrom .... statements to your R/*.R files if you want to use roxygen.
I agree with many things Hadley advocates; the wholesale use of 'roxygen' is not among them however.
I want good, carefully maintained help files with \link{}s, \eqn{}, etc etc
-> I edit my man/*.Rd files and I manually build NAMESPACE (so it ends up looking well organized, I can also add comments there, and I can even use
if(getRVersion() >= "3.2.0") { ...... } in the NAMESPACE file, something that's not easily possible with roxygen.
I'm working on an R package at present and trying to follow the best practice guidelines provided by Hadley Wickham at http://r-pkgs.had.co.nz. As part of this, I'm aiming to have all of the package dependencies within the Imports section of the DESCRIPTION file rather than the Depends since I agree with the philosophy of not unnecessarily altering the global environment (something that many CRAN and Bioconductor packages don't seem to follow).
I want to use functions within the Bioconductor package rhdf5 within one of my package functions, in particular h5write(). The issue I've now run into is that it doesn't have its S3 methods declared as such in its NAMESPACE. They are declared using (e.g.)
export(h5write.default)
export(h5writeDataset.matrix)
rather than
S3method(h5write, default)
S3method(h5writeDataset, matrix)
The generic h5write is defined as:
h5write <- function(obj, file, name, ...) {
res <- UseMethod("h5write")
invisible(res)
}
In practice, this means that calls to rhdf5::h5write fail because there is no appropriate h5write method registered.
As far as I can see, there are three solutions to this:
Use Depends rather than Imports in the DESCRIPTION file.
Use library("rhdf5") or require("rhdf5") in the code for the relevant function.
Amend the NAMESPACE file for rhdf5 to use S3methods() rather than export().
All of these have disadvantages. Option 1 means that the package is loaded and attached to the global environment even if the relevant function in my package is never called. Option 2 means use of library in a package, which while again attaches the package to the global environment, and is also deprecated per Hadley Wickham's guidelines. Option 3 would mean relying on the other package author to update their package on Bioconductor and also means that the S3 methods are no longer exported which could in turn break other packages which rely on calling them explicitly.
Have I missed another alternative? I've looked elsewhere on StackOverflow and found the following somewhat relevant questions Importing S3 method from another package and
How to export S3 method so it is available in namespace? but nothing that directly addresses my issue. Of note, the key difference from the first of these two is that the generic and the method are both in the same package, but the issue is the use of export rather than S3method.
Sample code to reproduce the error (without needing to create a package):
loadNamespace("rhdf5")
rdhf5::h5write(1:4, "test.h5", "test")
Error in UseMethod("h5write") :
no applicable method for 'h5write' applied to an object of class
"c('integer', 'numeric')
Alternatively, there is a skeleton package at https://github.com/NikNakk/s3issuedemo which provides a single function demonstrateIssue() which reproduces the error message. It can be installed using devtools::install_github("NikNakk/s3issuedemo").
The key here is to import the specific methods in addition to the generic you want to use. Here is how you can get it to work for the default method.
Note: this assumes that the test.h5 file already exists.
#' #importFrom rhdf5 h5write.default
#' #importFrom rhdf5 h5write
#' #export
myFun <- function(){
h5write(1:4, "test.h5", "test")
}
I also have put up my own small package demonstrating this here.
I am writing an R package. Generally, I have some functions that they are not useful for external uses. So when I put them in Namespace file, it causes an error about documentation of functions. On the other hand, if I remove them from Namespace file, it causes another problem, Function not found. So, is there any way of calling a function without a need of writing documentations?
As Andrie commented if you want to include the function in the R package you need to put it inside a folder (e.g. packageparent/R/) and declare in NAMESPACE. You do not put a function in NAMESPACE.
IF you do not want to include it in your package, none of your functions in your package shall call this function, otherwise the package does not compile. You still can include this function in your package and not write any documentation for it.
To use this function outside your package just source it
I've hit an issue trying to import a package (namely, 'robfilter') inside one of my own packages. One of its methods that I am trying to use, adore.filter, is failing at this line:
data(critvals)
With error 'data set 'critvals' not found'.
The function works fine if I load the library via require(robfilter). However, this means that in order to use my custom package which calls adore.filter, I will have to load my own package, and then load robfilter. Not a huge problem but slightly annoying.
I'm not sure if the problem is that there is an extra step I need to do in order to make critvals visible within my package, or if perhaps there is something the package author needed to do (and hasn't done) to add critvals to its package namespace; there is no sign of 'critvals' in the robfilter NAMESPACE file. I haven't encountered this issue before and don't really understand how the use of data() inside a package is supposed to work.
There are two solutions as far as I know:
Either ask the robfilter Maintainer to put the data needed by robfiler in the internal data file of robfilter. (R/sysdata.rda)
Or make your package Depends on robfilter
So it works if you put robfilter in the depends section of your description file. But in my case (both are my packages), I was trying to avoid the Depends solution as it loads the imported package and also any other package will need to depend ont its imported package... See my question is quite a duplicate of yours but not in the same context.