[R] Extracting elements out of list in list in list

[Rainer M Krug]

Hi

Consider the following variable:

--8<---------------cut here---------------start------------->8---
x1 <- list(
  A = 11,
  B = 21,
  C = 31
)

x2 <- list(
  A = 12,
  B = 22,
  C = 32
)

x3 <- list(
  A = 13,
  B = 23,
  C = 33
)

x4 <- list(
  A = 14,
  B = 24,
  C = 34
)

y1 <- list(
  x1 = x1,
  x2 = x2
)

y2 <- list(
  x3 = x3,
  x4 = x4
)

x <- list(
  f1 = y1,
  f2 = y2
)
--8<---------------cut here---------------end--------------->8---


To extract all fields named "A" from y1, I can do

,----
| > sapply(y1, "[[", "A")
| x1 x2 
| 11 12
`----

But how can I do the same for x?

I could put an sapply into an sapply, but this would be less then
elegant.

Is there an easier way of doing this?

Thanks,

Rainer

-- 
Rainer M. Krug
email: Rainer<at>krugs<dot>de
PGP: 0x0F52F982
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