R help - Jan 2006 - "Missing value representation in Excel before extraction to R with RODBC"

Dear list,

How should missing values be expressed in Excel before extraction to R 
via RODBC. I'm bewildered. Sometimes the representation with NA in Excel 
appears to work and shows up in R as <NA> but sometimes the use of NA in 
Excel changes the whole vector to NA's. Blank or nothing or NA as 
representation for missing values in Excel with dateformat gives NA's of 
the whole vector in R but with  general format in Excel gives blanks for 
missing values in R. How should I represent missing values in Excel?


Best wishes and thanks for any help
Fredrik Lundgren

Hi

I believe it has something to do with the column identification 
decision. When R decides what is in a column it uses only some values 
from the beginning of a file.

I do not use RODBC as read.delim("clipboard", ...) is usually more 
convenient but probably there is a way how to tell RODBC what is in 
the column instead of let R decide from the top of the file.

But I may be completely mistaken.

HTH
Petr


On 6 Jan 2006 at 20:47, Fredrik Lundgren wrote:

From:           	"Fredrik Lundgren" <fredrik.bg.lundgren at
bredband.net>
To:             	"R-help" <r-help at stat.math.ethz.ch>
Date sent:      	Fri, 6 Jan 2006 20:47:29 +0100
Subject:        	[R] "Missing value representation in Excel before
extraction to R
	with RODBC"
> Dear list,
> 
> How should missing values be expressed in Excel before extraction to R
> via RODBC. I'm bewildered. Sometimes the representation with NA in
> Excel appears to work and shows up in R as <NA> but sometimes the use
> of NA in Excel changes the whole vector to NA's. Blank or nothing or
> NA as representation for missing values in Excel with dateformat gives
> NA's of the whole vector in R but with  general format in Excel gives
> blanks for missing values in R. How should I represent missing values
> in Excel?
> 
> 
> Best wishes and thanks for any help
> Fredrik Lundgren
> 
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
Petr Pikal
petr.pikal at precheza.cz