当在另一个包中定义对象时，如何在R中调用新函数？

Question

Suppose I'm creating a package and I'd like to define a function that creates an object where the object is defined in another package.

For example: get_empty_mtx <- function() return(new("dgCMatrix"))

If I type library(Matrix) , this will work, but when I'm making my own package, I like to use :: when referencing things from other packages. I can't do Matrix::new("dgCMatrix") as new is not a function from the Matrix package.

Answer 1

You can use the getClassDef function to get a class definition from a specific package and then call new() on that. For example

new(getClassDef("dgCMatrix", getNamespace("Matrix")))

and new(getClassDef("dgCMatrix", "Matrix")) also seems to work despite the documtation saying where should be an environment.