[R] Complicated For Loop (to me)

[Don MacQueen]

You're looking for the assign() function.

See the first example in the help page for assign()

Something like
   assign( paste( j,'.cd',i,'es.wash',sep='') , 1 )
instead of
    names.cd[i].es.wash <- 1

paste() assembles the name as a character string, and then assign() 
assigns a value to a variable with that name.

-Don

At 8:41 AM -0800 11/9/09, agm. wrote:
>Hello,
>
>I'm trying to run a loop that will subset my data into specific sets by
>regions and by race/ethnicity.  I'm trying to do this fairly compactly, and
>I cannot get this to work. 
>
>A "simple" version of the code that I am trying to run is:
>
>names <- c("white", "black", "asian", "hispanic")
>for(j in names){
>for(i in 1:9){
>names.cd[i].es.wash <- 1
>es.cd[i].names.w <- names.cd[i].es.wash +1
>} ; }
>
>I want the loop to create these variables so that I would have for example:
>"white.cd1.es.wash" through "white.cd9.wash" and then the same for black,
>hispanic, and asian
>
>(However, none of these variables have been created yet outside of the loop)
>
>
>When I try to run this, I get the following error message:
>
>Error: unexpected symbol in:
>"for(i in 1:9){
>names.cd[i].es.wash"
>
>Any idea what I am doing wrong?  Thanks in advance for your help!  I am
>still trying to get my hands around this programming syntax
>
>--
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>Sent from the R help mailing list archive at Nabble.com.
>
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062