在编写自己的R包时，我似乎无法正确导入其他包

Question

Alright, first attempt at writing an R package and I'm stuck. Here's how I create the package:

package.skeleton("pkg",code_files=some.filenames)
roxygenize("okg")

I'm using roxygen2 and have the following imports in my "pkg-package.R" file:

@import data.table zoo lubridate

From a terminal, I then run:

R CMD build pkg
R CMD check pkg
R CMD install pkg

During the check phase, I get the following warnings:

** preparing package for lazy loading
Warning: replacing previous import 'hour' when loading 'lubridate'
Warning: replacing previous import 'mday' when loading 'lubridate'
Warning: replacing previous import 'month' when loading 'lubridate'
Warning: replacing previous import 'wday' when loading 'lubridate'
Warning: replacing previous import 'week' when loading 'lubridate'
Warning: replacing previous import 'yday' when loading 'lubridate'
Warning: replacing previous import 'year' when loading 'lubridate'
** help
* installing help indices
** building package indices ...
** testing if installed package can be loaded
Warning messages:
1: replacing previous import 'hour' when loading 'lubridate'
2: replacing previous import 'mday' when loading 'lubridate'
3: replacing previous import 'month' when loading 'lubridate'
4: replacing previous import 'wday' when loading 'lubridate'
5: replacing previous import 'week' when loading 'lubridate'
6: replacing previous import 'yday' when loading 'lubridate'
7: replacing previous import 'year' when loading 'lubridate'

I'm really not sure what to make of those, but they seem like typical warnings from overwriting stuff in namespace. In any case, I am able to install the package, but here's what happens when I try to use it:

library(pkg)
Overriding + and - methods for POSIXt, Date and difftime
Warning messages:
1: replacing previous import 'hour' when loading 'lubridate'
2: replacing previous import 'mday' when loading 'lubridate'
3: replacing previous import 'month' when loading 'lubridate'
4: replacing previous import 'wday' when loading 'lubridate'
5: replacing previous import 'week' when loading 'lubridate'
6: replacing previous import 'yday' when loading 'lubridate'
7: replacing previous import 'year' when loading 'lubridate'
d <- my.function(arg1, arg2)
Error in MATCH(x, x) : could not find function "MATCH"

Using traceback(), I found out that this is being generating during a call to merge.zoo(). So I tried loading zoo by hand during my R session and voila, then the function works correctly without the error message.

I have tried changing the ordering of the imports by hand in both the "pkg-package.R" file, as well as in NAMESPACE. Based on something I found elsewhere, I have not added any Imports or Depends to DESCRIPTION, however. Help?

Answer 1

The warnings are because data.table and lubridate both define a symbol hour , etc; see data.table::hour and lubridate::hour . You could avoid this by importing just the functions from lubridate / data.table that you want, rather than the whole package; a standard NAMESPACE file would contain

importFrom(lubridate, hour)

for instance. In roxygen2 you would use the tag:

@importFrom lubridate hour

The MATCH problem is probably because merge is dispatching incorrectly, probably because zoo should have in its name space S3method(merge, zoo) rather than export(merge.zoo) , as described in Writing R Extensions, 1.6.2. The solution here is to contact the maintainer of zoo , packageDescription('zoo')$Maintainer (the maintainer is sufficiently versed in R that I feel like I've mis-diagnosed...).

Answer 2

作为MATCH错误的临时解决方法，我已经成功列出了包的DESCRIPTION文件的Depends:部分下的zoo包。