r - 如何查看元素是否包含在列表中

Question

我有以下列表

catlist <- list(c("< 30 days","1-3 months","4-6 months"),c("7-12 months"),c("1-3 years"),
                  c("4-5 years","5+ years","never"))

我给的名字

names(catlist) <- 1:length(catlist)

此外，我还有一个data.table

library(data.table)
tmp <- data.table(variable = c("never","1-3 years"))

我想做的是在 tmp 中创建一个新变量 (new_variable)，它的值将是 catlist 的名称 其中的值变量的落入

所以最后我想以这个结束

> tmp
    variable new_variable
1:     never            4
2: 1-3 years            3

我尝试创建一个函数，但它不起作用

trans_dummy_multiple <- function(dt, var, catlist){

  dt <- tmp # for testing
  var <- "variable" # for testing
  catlist <- list(c("< 30 days","1-3 months","4-6 months"),c("7-12 months"),c("1-3 years"),
                  c("4-5 years","5+ years","never")) # for testing
  names(catlist) <- 1:length(catlist)
  dt[,new_variable:=lapply(catlist,function(x){if(x%in%get(var)){names(x)}})]


}

Answer 1

尝试:

scl<-setDT(stack(catlist))
scl[tmp,on=c(values="variable")]
#      values ind
#1:     never   4
#2: 1-3 years   3