[R] read separate columns from an Excel sheet

[Gabor Grothendieck]

On Sun, Feb 26, 2012 at 2:58 PM, Ivette <iva_mihaylova at mail.ru> wrote:
> Hello,
>
> Lets suppose I have an Excel sheet with 9 columns of data. How to tell R to
> read for example column 1 and 7 of this sheet? I know only the usual code
> without specifying columns:
>
> library(gdata)
> a <- read.xls("file.xls", sheet=1)                # reads in the 1st sheet
>

Its pretty much the same as if you were using read.table, viz.

read.xls("file.xls")[c(1, 7])

or if you know that there are nc columns:

nc <- ...
read.xls("file.xls", colClasses = replace(rep("NULL", nc), c(1, 7), NA))

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