[R] making a dataframe out of lapply() result

[Remko Duursma]

Mahbub's solution 

data.frame(t(sapply(...)))

is much faster than

do.call("rbind", lapply(...))

as tested on a larger dataset.

Thanks everyone,

Remko Duursma
--

On Tue, 15 Apr 2003 22:10:28  
 Mahbub Latif wrote:
>you can try this,...
>data.frame(t(sapply(tester.L, function(x) x <- x[1,]
>)))
>
>Mahbub.
>
>--- Remko Duursma <den.duurs at lycos.com> wrote:
>> Dear R-helpers,
>> 
>> i have a question on how to vectorize this problem:
>> 
>> i have a dataframe:
>> 
>> tester <-
>> data.frame(groups=c("A","A","B","B","C","C"),
>> one=c(1,1,2,2,3,3), two=c(6,6,7,7,8,8))
>> 
>> # i split it into a list
>> tester.L <- split(tester, tester$groups)
>> 
>> # And want to keep only the first item in each:
>> lapply(tester.L, function(x) x <- x[1,] )
>> 
>> 
>> How do i make a dataframe out of the last result,
>> which looks like "tester", without looping? (i can
>> use rbind in a for loop, but is rather slow)
>> 
>> thanks for your help,
>> 
>> Remko Duursma
>> 
>> 
>>
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