Question

我有两个列表：

myList1 <- list(c("","VNW","SPEC","N","BW" ), c("","WW","N","SPEC","ADJ"),c( "","WW","N"), c("","WW","N"), c("","ADJ","N","WW"), c( "","ADJ","N"))

myList2 <- list(c( "","125141","44","4945","3"), c("","114146","77","19","3"), c("","4359","695"), c("","1372","623"), c("","209","71","1"), c( "","33","3"))

我还有两种形式的索引：

MyNIndices <- c(4,3,3,3,3,3)

或

MyNIndices <- list (4,3,3,3,3,3)

MyNIndices反映MyList1中每个向量的哪个元素上出现“ N”？

现在，我希望能够索引到myList2上的相同索引，以便可以获得与N对应的值。所以，我想作为输出

MyFinalValues <- c(4945, 77, 695, 623, 71, 3)

OR

MyFinalValues <- list(4945, 77, 695, 623, 71, 3)

我该怎么做？

Answer 1

在tidyverse中，您可以

library(purrr)
map2(myList2,MyNIndices, `[[`)

或者，如果您想返回数字矢量

map2_chr(myList2,MyNIndices, `[[`) %>% 
    as.numeric()

Answer 2

您可以尝试

MyFinalValues <- mapply(function(x,i) x[i],x=myList2, i=MyNIndices)
if(is.list(MyNIndices)) MyFinalValues=list(MyFinalValues)

R：如果向量构成列表的一部分，如何从向量中获取元素？

2 个答案: