[R] access sublists by a variable

[Antje Gruner]

Dear list,

I'd like to access the elements of a list within another list with the
help of a variable.

dict <- list(  "24" = c(1,2,3,6,12,24,48,72,96,120,144,168,720),
          "168" = c(1,12,24,48,72,96,120,144,168,336,504,672),
         "8760" = c(1,24,168,730,4380,8760)
        )

dict$"24" works fine, but

a <- "24"
dict$a

returns  NULL

Unfortunately dict[a] does not work for me, because I see no possibility
to access the inner elements of list "24" in that case
i.e. dict[a][1] returns the whole list and not the first element.

What is the correct syntax to access those elements with the help of a
variable?
Thanks in advance

Antje