[R] How to set a filter during reading tables

[Juliet Hannah]

One can use colClasses to set which columns get read in. For the
columns you don't
want you can set those to NULL. For example,

cc <- c("NULL",rep("numeric",9))

myData <- read.table("myFile.txt",header=TRUE,colClasses=cc,nrow=numRows).


On Wed, May 27, 2009 at 12:27 PM,  <guox at ucalgary.ca> wrote:
> We are reading big tables, such as,
>
> Chemicals <-
> read.table('ftp://ftp.bls.gov/pub/time.series/wp/wp.data.7.Chemicals',header
> = TRUE, sep = '\t', as.is =T)
>
> I was wondering if it is possible to set a filter during loading so that
> we just load what we want not the whole table each time. Thanks,
>
> -james
>
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