Aggregate is highly confusing (and i would have appreciated if you used my
example instead, i don't get it to do anything sensible on my stuff).
And this seems not what i asked for anyway. This may be a named list but not
named and structured as i want it at all.
happy Christmas too
On 20.12.2012, at 15:48, Chris Campbell wrote:
> Dear Jessica
>
> Aggregate is a function that allows you to perform loops across multiple
> variables.
>
> tempData <- data.frame(height = rnorm(20, 100, 10),
> width = rnorm(20, 50, 5),
> par1 = rnorm(20))
>
> tempData$htfac <- cut(tempData$height, c(0, 100, 200))
> tempData$wdfac <- cut(tempData$width, c(0, 50, 100))
>
> doSomething <- function(x) { mean(x) }
>
> out <- aggregate(tempData["par1"], tempData[c("htfac", "wdfac")],
> doSomething)
>
> # out is a data frame; this is a named list.
> # use as.list to remove the data.frame class
>
>> as.list(out)
>
> $htfac
> [1] (0,100] (100,200] (0,100] (100,200]
> Levels: (0,100] (100,200]
>
> $wdfac
> [1] (0,50] (0,50] (50,100] (50,100]
> Levels: (0,50] (50,100]
>
> $par1
> [1] -1.0449563 -0.3782483 -0.9319105 0.8837459
>
>
>
> I believe you are seeing an error similar to this one:
>
>> out[[1:3]] <- 1
> Error in `[[<-`(`*tmp*`, i, value = value) :
> recursive indexing failed at level 2
>
> This is because double square brackets for lists can only set a single list
> element at once; grid[1, ] is longer.
>
> Happy Christmas
>
> Chris
>
>
> Chris Campbell
> Tel. +44 (0) 1249 705 450 | Mobile. +44 (0) 7929 628 349
> mailto:ccampb...@mango-solutions.com | http://www.mango-solutions.com
> Mango Solutions
> 2 Methuen Park
> Chippenham
> Wiltshire
> SN14 OGB
> UK
>
> -----Original Message-----
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
> Behalf Of Jessica Streicher
> Sent: 20 December 2012 12:46
> To: R help
> Subject: [R] Filling Lists or Arrays of variable dimensions
>
> Following problem:
>
> Say you have a bunch of parameters and want to produce results for all
> combinations of those:
>
> height<-c("high","low")
> width<-c("slim","wide")
>
> then what i used to do was something like this:
>
> l<-list()
> for(h in height){
> l[[h]]<-list()
> for(w in width){
> l[[h]][[w]] <- doSomething()
> }
> }
>
> Now those parameters aren't always the same. Their number can change and the
> number of entries can change, and i'd like to have one code that can handle
> all configurations.
>
> Now i thought i could use expand.grid() to get all configurations ,and than
> iterate over the rows, but the problem then is that i cannot set the values
> in the list like above.
>
> grid<-expand.grid(height,width)
> l[[as.character(grid[1,])]] <-1
> Error in `[[<-`(`*tmp*`, as.character(grid[1, ]), value = 1) :
> no such index at level 1
>
> This will only work if the "path" for that is already existent, and i'm not
> sure how to build that in this scenario.
>
> I then went on and built an array instead lists of lists, but that doesn't
> help either because i can't access the array with what i have in the grids
> row - or at least i don't know how.
>
> Any ideas?
>
> I'd prefer to keep the named lists since all other code is built towards this.
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
> --
>
> LEGAL NOTICE
>
> This message is intended for the use of the named recipient(s) only and may
> contain
> confidential and / or privileged information. If you are not the intended
> recipient, please
> contact the sender and delete this message. Any unauthorised use of the
> information
> contained in this message is prohibited.
>
> Mango Business Solutions Limited is registered in England under No. 4560258
> with its
> registered office at Suite 3, Middlesex House, Rutherford Close, Stevenage,
> Herts, SG1 2EF,
> UK.
>
> PLEASE CONSIDER THE ENVIRONMENT BEFORE PRINTING THIS EMAIL
>
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
