[R] How to iteratively extract elements out of a list

[Patrick Connolly]

On Sat, 26-Aug-2006 at 09:57AM +0100, Patrick Burns wrote:

|>  > sub.m <- lapply(m, function(x)x[x>2])
|>  > sub.m
|> [[1]]
|> [1] 3 4
|> 
|> [[2]]
|> [1] 4 5
|> 
|> [[3]]
|> [1] 4
|> 
|>  > sub.m[unlist(lapply(sub.m, function(x) length(x) == 2))]
|> [[1]]
|> [1] 3 4
|> 
|> [[2]]
|> [1] 4 5
|> 
|>  > sub4.m <- lapply(m, function(x)x[x>4])
|>  > sub4.m[unlist(lapply(sub4.m, function(x) length(x) > 0))]
|> [[1]]
|> [1] 5

Or slightly shorter in this case:

sub.m[sapply(sub.m, function(x) length(x) == 2)]

etc.



-- 
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.   
   ___    Patrick Connolly   
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