r - Create list with depth equal 2 -


i have list depth equal 2. subscript list described in following example:

my.list<-list(   a=list(     a1=1:10,     a2=11:20),   b=list(     b1=21:30,     b2=31:40),   c=list(     c1=41:50,     c2=51:60) ) # choose specific item  my.list[[2]][[2]][[3]]  # choose first items a1,a2,b1,b2,c1,c2 test<-list() for(i in 1:3)   (j in 1:2)test[[i]][[j]]<-my.list[[i]][[j]][[1]]  test  error in `*tmp*`[[i]] : subscript out of bounds

but won't work since list created has no lists within it. works this:

test<-list() for(i in 1:3)   (j in 1:2)test[[i]]<-my.list[[i]][[j]][[1]]

and then

test<-list() for(i in 1:3)   (j in 1:2)test[[i]][[j]]<-my.list[[i]][[j]][[1]]  test

gives:

[[1]] [1]  1 11  [[2]] [1] 21 31  [[3]] [1] 41 51

...

does following code solve problem?

lapply(my.list, sapply, head, 1)

gives first element of each vector each entry in my.list:

$a a1 a2   1 11   $b b1 b2  21 31   $c c1 c2  41 51

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