Re: [R] reading only some columns from a table

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Mon 30 Oct 2006 - 10:41:36 GMT

Here is an example:

> Lines <- "conid person construct

+ 1 1 offence
+ 2 1 insight"
>
> read.table(textConnection(Lines), header = TRUE,
+ colClasses = c(person = NULL))
  conid person construct

1     1      1   offence
2     2      1   insight




On 10/30/06, Amir Safari <amsa36060@yahoo.com> wrote:
>
> Thank you so much for reply. I tried to do your suggested idea. It did not
> work. what could be my mistake ? I got the same result with and without
> colClasses=c() arguement. What could be the reason? even using header=TRUE
> the result change slightly but not into desired one.
>
>
>
> Gabor Grothendieck <ggrothendieck@gmail.com> wrote:
> See the colClasses argument of read.table.
>
> e.g.
>
> read.table("myfile", header = TRUE, colClasses = c(person = NULL))
>
> assuming you don't want the column labelled person in the header.
>
> On 10/30/06, Amir Safari wrote:
> >
> >
> > Dear R users,
> > Sometimes it is needed to read only some columns from a table, in
> particulare for high frequency data. How it is possible to read just some
> certain columns using read.table ( ). The reason could be keeping space in R
> and in particular accelerating in reading data when the number of rows are
> huge and some of them are not needed.
> > Thank you very much,
> > Amir
> >
> >
> > ---------------------------------
> >
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> >
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>
>
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