问题
When loading the RTextTools package from CRAN, I get the following warnings:
Warning messages:
1: replacing previous import ‘head’ when loading ‘utils’
2: replacing previous import ‘tail’ when loading ‘utils’
How do I get rid of these warnings? I'm the author of the package, so I can manipulate the source code; I'm looking for a solution that gets rid of the warnings rather than suppresses them. They seem to have appeared when I upgraded to R 2.14. Thank you in advance!
回答1:
This is not your issue - it's an issue in the glmnet package that you depend on: it explicitly imports all functions from both Matrix and utils but in the wrong order which causes a conflict since they both define head and tail (Matrix depends on utils so utils must be first). It is easy to fix - the order of imports has to be reversed in the glmnet/NAMESPACE but only the maintainer of glmnet can do that.
PS: This would be better asked on R-devel
回答2:
In general, this problem is often caused by having import(somepackage) in the namespace as well as importFrom(somepackage, somefunction).
Equivalently, using roxgyen2, having both #' @import somepackage and #' @importFrom somepackage somefunction.
The best practice solution is to remove the import statement ans keep only importFrom.
来源：https://stackoverflow.com/questions/8662285/warning-replacing-previous-import-head-when-loading-utils-in-r