Reorder list elements

Question

I have a simple problem, but can’t find a straightforward answer for it. I have the following type of list

my.list=list(a=c(1,2,3),random=1,list=matrix(1:10,nrow=2))

of which I would like to change the order of list elements (here: 'a','random' and 'list') according to the order of another list ('a','list','random'), or thus a vector of list names: names(my.other.list):

my.other.list=list(a=c(4,5,6),list=matrix(101:110,nrow=2),random=2)

so the goal is to obtain this list:

my.wanted.list=list(a=c(1,2,3),list=matrix(1:10,nrow=2),random=1)

Note that both list (my.list and my.other.list) have the same list names, and that these can not be sorted alphabetically or so.

I created this loop:

my.wanted.list=list()
for(i in 1:length(my.list)){
  my.wanted.list[[i]]=my.list[[names(my.other.list)[i]]]
}
names(my.wanted.list)=names(my.other.list)

But that seems like a time consuming solution for a seemingly simple problem. Especially if the lists are bigger. So is there a simpler way of doing this?

Thank you.

Answer 1

You could simply do this using the subsetting mechanism of list with names.

my.list = list( a = c(1,2,3), random=1, list = matrix(1:10,nrow=2))

my.other.list = list(a=c(4,5,6), list=matrix(101:110,nrow=2),random=2)

without any package

my.list[names(my.other.list)]
#> $a
#> [1] 1 2 3
#> 
#> $list
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    1    3    5    7    9
#> [2,]    2    4    6    8   10
#> 
#> $random
#> [1] 1

or you could use a package as rlist

my.list %>% 
  list.subset(names(my.other.list))
#> $a
#> [1] 1 2 3
#> 
#> $list
#>      [,1] [,2] [,3] [,4] [,5]
#> [1,]    1    3    5    7    9
#> [2,]    2    4    6    8   10
#> 
#> $random
#> [1] 1

it reoder your first list in the order of the name vector you use for subsetting.