有没有一种简洁/简单的方法来处理此data.table R代码？ [英] Is There A Neat/Simplest Way To This data.table R Code?

问题描述

OECD数据中的STRATUM很长，为简单起见，我使用了这个名称，并希望将其简化为更简短，更精确的命名，如下代码所示。

The STRATUM from OECD data is so long, for simplicity I put this name and would like to simplified it to a more short and precise naming as in the code below.

pisaMas[,`:=`
             (SchoolType = c(ifelse(STRATUM == "National Secondary School", "Public", 
                                    ifelse(STRATUM == "Religious School", "Religious", 
                                           ifelse(STRATUM == "MOE Technical School", "Technical",0)))))]
pisaMas[,table(SchoolType)]

我想知道是否有简单的方法可以使用data.table包来解决此问题。

I would like to know if there are a simple way to this problems, using data.table package.

推荐答案

data.table 的当前开发版本具有新功能 fcase （根据SQL CASE 时的情况进行建模）：

Current development version of data.table has new function fcase (modeled after SQL CASE WHEN) for this situation:

pisaMas[ , SchoolType := fcase(
  STRATUM == "National Secondary School", "Public", 
  STRATUM == "Religious School", "Religious", 
  STRATUM == "MOE Technical School", "Technical",
  default = ''
)]
pisaMas[ , table(SchoolType)]

要获取开发版本，请尝试

To get the development version, try

install.packages(
  'data.table', type = 'source',repos = 'http://Rdatatable.github.io/data.table'
)

如果简单安装无效，则可以查看Installation Wiki以获得更多详细信息：

If the simple install doesn't work, you can check the Installation wiki for some more details:

https：// github.com/Rdatatable/data.table/wiki/Installation

您也可以使用查找表解决此问题，有关详细信息，请参见此问答：

You can also solve this with a lookup table, see this Q&A for details:

https://stackoverflow.com/a/36391018/3576984

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