[R] Combining values from a data.frame row with matrix rownames.

[Gil Gamesh]

Terrific!

Many thanks, Josh, you put me on the right path with the tip re dput
and the remark about factors.

Using "stringsAsFactors=FALSE" in my read.table and then
"IndexList <- c( unlist(seed_panel[ i, ]), rownames( Control[ j, ] ) )"
did the trick.

Your help is hugely appreciated. Thanks again!

G

On 18 August 2010 06:46, Joshua Wiley <jwiley.psych at gmail.com> wrote:
> Hi,
>
> I believe you are looking for ?unlist.  Here is something that does
> what I think you want with data that is my best guess at what yours is
> like (if the data in seed_panel is stored as factor, you will probably
> need to convert it first somehow).
>
>> seed_panel <- data.frame(V2 = "507D22", V3 = "518F15", stringsAsFactors = FALSE)
>> Control <- matrix(1:4, ncol = 2, dimnames = list(c("505E01", "etc"), c("Col1", "Col2")))
>>
>> unlist(c(seed_panel[1, ], rownames(Control)[1]))
>      V2       V3
> "507D22" "518F15" "505E01"
>
> As a future suggestion, doing something like
> dput(head(your_data_name)) is a simple way to provide us with the
> first few rows of your data.
>
> Cheers,
>
> Josh
>
> On Tue, Aug 17, 2010 at 10:36 AM, Gil Gamesh <gamesh.g at gmail.com> wrote:
>> Apologies, I neglected to check that the email was plain text. Here is
>> a the text of the previous email.
>>
>>
>> Hello,
>>
>> I am trying to iteratively build a build a panel of variables to
>> discriminate between two groups.
>>
>> My starting position is a matrix of experimental data and I have a function
>> that will work through all pairs of variables and produce sensitivities,
>> specificities and p-values for each pair and write it to a file (above
>> particular cut-offs).
>>
>> I have a second function that will read that file in and use the pairs as a
>> 'seed' adding a third variable from the original matrix and performing the
>> same calculations and writing a new file.
>>
>> My aim is to iterate through this procedure five or six times.
>>
>> My difficulty is making the index vector to extract the values I need from
>> the matrix of experimental data.
>>
>> The seed panel is a row in a data.frame:
>>
>> print(seed_panel[i,])
>>
>>      V2     V3
>> 1 507D22 518F15
>>
>>
>> and the variable to add to it is a rowname of the experimental matrix:
>>
>> print(rownames(Control[j,]))
>>
>> [1] "505E01"
>>
>> I haven't found a way to combine these three - I would like a vector
>> c("507D22","518F15","505E01") - to subscript the matrix of experimental
>> data.
>>
>> IndexList <- c(as.vector( seed_panel[ i, ], mode="any"), rownames( Control[
>> j, ] ) )
>>
>> Gives:
>>
>> $V2
>> [1] 507D22
>> 18 Levels: 507D22 518F15 522C17 522K21 523A19 528H06 528P11 530H18 ...
>> 585K18
>>
>> $V3
>> [1] 518F15
>> 20 Levels: 518F15 522C17 522K21 523A19 528H06 528P11 530H18 534L09 ...
>> 590C18
>>
>> [[3]]
>> [1] "505E01"
>>
>> and I haven't had any luck with variations on this that I've tried.
>>
>>
>> Many thanks in advance for any help.
>>
>> ______________________________________________
>> R-help at 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.
>>
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> University of California, Los Angeles
> http://www.joshuawiley.com/
>