[R] Assignments in loops

[Thomas Lumley]

On Tue, 30 Dec 2003, Murray Jorgensen wrote:

> Thanks to Andy, Peter and Roger for drawing my attention to assign(), which
> is just what I needed and works fine.

I will just add the usual note that when you find yourself using assign()
it is a good idea to think very carefully about why you can't use a list
with named components instead of separate variables.


	=thomas


>
> Murray
>
> At 14:11 30/12/2003 +1300, Murray Jorgensen wrote:
> >Greetings all. Any help with the following would be appreciated.
> >
> >I want to create a data frame for each file in a directory. The following
> >code does not work but it may show what I am trying to do:
> >
> >carmakes <- c('BMW','Chrysler','Citroen','Fiat','Ford','Holden','Honda',
> >'Mercedes','MG','Mitsubishi','Nissan','Peugeot','Renault','Subaru','Toyota',
> >'VW')
> >for (brand in carmakes) {
> >   fyle <- paste("c:/data/cars03/",brand,".txt",sep="")
> >   brand <- read.table(fyle, header = TRUE, sep = "\t",na.strings =
> >            c("-","POA"), colClasses=c("character",rep("numeric",7)),
> >             comment.char = "#")
> >}
> >
> >I need something like an unquote() function that will allow the "brand" on
> >the LHS of the assignment to be treated as an object name instead of a
> >character string.
> >
> >Murray
> >
> >
> >
> >
> >
> >
> >Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
> >Department of Statistics, University of Waikato, Hamilton, New Zealand
> >Email: maj at waikato.ac.nz                                Fax 7 838 4155
> >Phone  +64 7 838 4773 wk    +64 7 849 6486 home    Mobile 021 1395 862
> >
> >______________________________________________
> >R-help at stat.math.ethz.ch mailing list
> >https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> >
> Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
> Department of Statistics, University of Waikato, Hamilton, New Zealand
> Email: maj at waikato.ac.nz                                Fax 7 838 4155
> Phone  +64 7 838 4773 wk    +64 7 849 6486 home    Mobile 021 1395 862
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle