Question

data.table DT具有以下结构。请注意，region_code是一个有4个级别的因子。我想改变这些水平。

Classes ‘data.table’ and 'data.frame':  28 obs. of  4 variables:
 $ scenario   : chr  "2010" "SSP2-NoCC" "SSP1-NoCC" "SSP3-NoCC" ...
 $ region_code: Factor w/ 4 levels "highInc","lowInc",..: 2 2 2 2 2 2 2 3 3 3 ...
 $ region_name: chr  "Low income" "Low income" "Low income" "Low income" ...
 $ value      : num  17.8 18.6 20.1 17.9 18.3 ...
 - attr(*, ".internal.selfref")=<externalptr> 

Here is the output of head(DT) before I try to change the order of the levels.

    scenario region_code region_name    value
1:      2010      lowInc  Low income 17.76127
2: SSP2-NoCC      lowInc  Low income 18.55630
3: SSP1-NoCC      lowInc  Low income 20.08646
4: SSP3-NoCC      lowInc  Low income 17.87970
5: SSP2-GFDL      lowInc  Low income 18.30423
6: SSP2-IPSL      lowInc  Low income 18.36362

然后我尝试用

更改region_code的级别顺序

levels(DT$region_code) <- c("lowInc", "lowMidInc", "upMidInc", "highInc")

现在head（DT）的输出是

    scenario region_code region_name    value
1:      2010   lowMidInc  Low income 17.76127
2: SSP2-NoCC   lowMidInc  Low income 18.55630
3: SSP1-NoCC   lowMidInc  Low income 20.08646
4: SSP3-NoCC   lowMidInc  Low income 17.87970
5: SSP2-GFDL   lowMidInc  Low income 18.30423
6: SSP2-IPSL   lowMidInc  Low income 18.36362

请注意，例如，region_code的第一行值已更改lowMidInc，但所有其他元素都相同。

如何保持行内容相同，只更改region_code列的level属性？

r更改数据表中的级别会更改行内容

0 个答案: