使用list中的对象作为lapply中的函数参数

Question

我试图学习不同的方法来使用列表中的对象作为FUN参数lapply.拿这个数据:

A <- list(a = matrix(0, ncol = 3, nrow = 3), b = matrix(0, ncol = 3, nrow = 3))
B <- list(a = matrix(1, ncol = 1, nrow = 3), b = matrix(1, ncol = 1, nrow = 3))
D <- mapply(FUN="list", A, B, SIMPLIFY=F, USE.NAMES=F)
D <- lapply(D, `names<-`, c("first", "second"))
D
[[1]]
[[1]]$`first`
     [,1] [,2] [,3]
[1,]    0    0    0
[2,]    0    0    0
[3,]    0    0    0

[[1]]$second
     [,1]
[1,]    1
[2,]    1
[3,]    1


[[2]]
[[2]]$`first`
     [,1] [,2] [,3]
[1,]    0    0    0
[2,]    0    0    0
[3,]    0    0    0

[[2]]$second
     [,1]
[1,]    1
[2,]    1
[3,]    1

期望的结果:

[[1]]
     [,1] [,2] [,3]
[1,]    0    0    0
[2,]    0    0    0
[3,]    0    0    0
[4,]    1    1    1

[[2]]
     [,1] [,2] [,3]
[1,]    0    0    0
[2,]    0    0    0
[3,]    0    0    0
[4,]    1    1    1

这就是我通常会这样做的方式:

lapply(D, function(x) rbind(x$first, as.numeric(x$second)))

现在我想知道是否有办法避免使用function(x)和重复所有那些x s.就像是:

lapply(D, "rbind", <args>)

我怎样才能让rbind(或任何其他函数)知道我指的是框架内的对象lapply？

谢谢,

K.

Answer 1

为了“避免使用function(x)和重复所有这些x”，我们可以使用with()：

lapply(D, with, rbind(first, as.numeric(second)))