[R] data.frame to array?

David Winsemius dwinsemius at comcast.net
Fri Apr 3 21:29:10 CEST 2009


I do not think that the form [[1:3]] is legit.

 > ltest <- list( "a", "b", "c", "d")
 > ltest[[1:3]]
Error in ltest[[1:3]] : recursive indexing failed at level 2

You might try with single brackets:
 > ltest[1:3]
[[1]]
[1] "a"

[[2]]
[1] "b"

[[3]]
[1] "c"

--  
David Winsemius



On Apr 3, 2009, at 2:45 PM, <rkevinburton at charter.net> wrote:

> I have a list of data.frames
>
>> str(bins)
>
> List of 19217
> $ 100026:'data.frame':	1 obs. of  6 variables:
>  ..$ Sku  : chr "100026"
>  ..$ Bin  : chr "T149C"
>  ..$ Count: int 108
>  ..$ X    : int 20
>  ..$ Y    : int 149
>  ..$ Z    : chr "3"
> $ 100030:'data.frame':	1 obs. of  6 variables:
> .......
> As you can see one 'column' is "Count". This list seems to contain  
> 19217 data.frames. I would like to create an array of 19217 integers  
> which hold the values of the "Count" column. I have tried the  
> obvious (to me):
>
> bins[[1:3]]$Count
>
> But that returns NULL instead of an array of length 3 that I was  
> expecting. Interestingly bins[[1]]$Count returns the first "Count"  
> in the list of data frames. How do I get all of the "Count"s?
>
> Thank you.
>
> Kevin




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