[R] RODBC vs gdata

[Gabor Grothendieck]

On Mon, Jan 9, 2012 at 1:02 PM, Christof Kluß <ckluss at email.uni-kiel.de> wrote:
> Hi
>
> one col in my Excel file contains many numbers. But on line 3000 and
> some other lines are strings like "FG 1". "RODBS" seems to omit this
> lines. "gdata" works, but is much slower.
>
> Is this a bug of RODBC or do I apply it wrong?
>
> Example with the same "file.xlsx"
>
>
> library(RODBC); excel <- odbcConnectExcel2007("file.xlsx")
> tab <- sqlQuery(excel, 'select * from "Table 1$"'); str(tab)
>
> col1: num  1 2 3 4 5 6 7 8 9 10 ...
>
> library(gdata); tab <- read.xls("file.xlsx", sheet=1); str(tab)
>
> col1: Factor w/ 51 levels "1","10","11",..: 1 12 23 34 41 42 43...

You might be able to speed up read.xls in gdata.  Try turning off
comment characters and setting colClasses, e.g.

DF <- read.xls(...whatever..., comment.char = "", colClasses = ...whatever...)

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