是否可以在R中一步来复制和修改列表? [英] Is it possible to duplicate and modify a list in one step in R?

问题描述

我发现自己经常这样做:

I find myself doing this a lot:

my_list <- list(a = list(b = "something"), c = 3, d = "a lot of other options") 

my_list_2 <- my_list
my_list_2$a$b <- "something_else"
my_list_2$c <- 5

我想知道是否有速记.像这样:

I was wondering if there was a shorthand for this. Something like:

my_list_2 <- xxxxx(my_list, list(a = list(b = "something_else"), c = 5))

更新:我的预期输出是:

my_list # unchanged
my_list_2 # list(a = list(b = "something_else"), c = 5, d = "a lot of other options") 

推荐答案

一种选择是使用?within:

within(my_list, {a$b = "something_else"; c = 5})
#$a
#$a$b
#[1] "something_else"
#
#
#$c
#[1] 5
#
#$d
#[1] "a lot of other options"

当然可以通过将结果分配给新对象(例如

Of course the duplication is possible in the same step by assigning the result to a new object, e.g.

my_list2 <- within(my_list, {a$b = "something_else"; c = 5})

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