如何在 R 包中加载依赖项? [英] How can I load dependencies in an R package?

问题描述

我正在开发一个 R 包，可以在 DESCRIPTIONS 文件中找到它

I am developing an R package where this is available in the DESCRIPTIONS file

Imports: 
    dplyr,
    ggplot2,
    ncdf4

我有一个使用第三个依赖项的示例函数

And I have an example function where I use the third dependency

testFun <- function(file, lat, long){
  ncfname <- file.path(file,fsep = .Platform$file.sep)
  xfile <- nc_open(ncfname) #Opens the NetCDF file
  lat <- ncvar_get(xfile, 'lat') #Extracts all latitudes

  ...Calculations

  return(XYZ)
}

当我构建并重新加载包并运行该函数时，它找不到函数nc_open".

When I Build and Reload the package, and I run the function, it could not find function "nc_open".

但是，当我用 ncdf4::nc_open

我是否应该为代码中使用的每个依赖项添加 packagename:: 前缀?还是我错过了什么?

Am I supposed to prefix packagename:: to every dependency I use in the code? or am I missing something?

通常，我希望从 DESCRIPTIONS 安装所有依赖项，并且它的功能无需每次都需要包前缀即可使用.

Ordinarily, I would like all the dependencies to be installed from the DESCRIPTIONS and it's functions available for use without requiring the package prefix everytime.

推荐答案

要么:

• 明确地在函数前面加上它来自的包:ncdf4::nc_open(...)

或者:

• 在您的 NAMESPACE 文件 importFrom(ncdf4, nc_open) 中添加一行，然后在您的代码中，调用不带包的函数:nc_open(...)

• add a line in your NAMESPACE file importFrom(ncdf4, nc_open) and then in your code, call the function without the package: nc_open(...)

除了为您要导入的每个函数添加 importFrom 行之外，您还可以使用 import(ncdf4) 从该包中获取所有内容.

Rather than adding an importFrom line for every function you want to import, you can also use import(ncdf4) to snarf everything from that package.

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