[R] how to process this in R

[Tony B]

I don't have R on the netbook I'm writing this from, but I *think* the
following will work:

> 1. how can i only read in the files with the string patterns ggg or fff as
> part of the file names?
>   for instance, I only need the file names with the ggg or fff in it
>      xxxxx_ggg_yyyyy_1.txt
>      yyyy_fff_yyyy_xxx.txt
>
>     i don't need to read in the files, such as xxxx_aaa_yyyy.txt

Maybe something like:
d <- "C:\\FilesFolder\\"
f <- list.files(path = d, pattern = "(ggg)|(fff)", full.names = TRUE)
x <- lapply(f, read.table, header = TRUE)


> 2.how cam rename the files:
>
>   for instance: xxxxx_ggg_yyyyy_1.txt ======> changed to ggg1a.txt

see ?file.rename

> 3.after the files read in, how can i only keep the rows with the aaa and
> bbb, everything elses show be removed from the files, but the files still
> remain the same file name?
>
>    for instance, in the xxxxx_ggg_yyyyy_1.txt file, it shouls looks like:
>  name    count
>
> 1. aaa    100
> 2. bbb    2000
> 3. aaa    300
> 4. bbb    400

Something along the following lines should work:
DF <- data.frame(name=rep(c("aaa", "bbb"), 2), count = c(100, 2000,
300, 400))

  name count
1  aaa   100
2  bbb  2000
3  aaa   300
4  bbb   400

subset(DF, name == "aaa")
  name count
1  aaa   100
3  aaa   300

HTH
Tony Breyal