[R] data.frame to array?

[Gavin Simpson]

On Fri, 2009-04-03 at 11:45 -0700, 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

sapply(bins, `[[`, "Count")

will get you this as a vector.

HTH

G

> 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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