[R] read.table, NA assignment, and sep

[Peter Dalgaard]

Juliet Hannah wrote:
> I place the following data in a file
>
> id 	 rs835 	 rs169 	 rs174
> 1001 	 CC 	 GG 	 CC
> 10032 	 CC 	 GG 	 CC
> 10066 	 CC 	 NA 	 CC
>
> If I read it in as
> tempDat <- read.table("tempDat.txt",na.strings="NA",header=TRUE)
>
> I get the following.
>
>      id rs835 rs169 rs174
> 1  1001    CC    GG    CC
> 2 10032    CC    GG    CC
> 3 10066    CC  <NA>    CC
>
> NA has been assigned a missing value.
>
> If I add the separator
>
> tempDat <- read.table("tempDat.txt",na.strings="NA",sep="\t",header=TRUE)
> tempDat
>      id rs835 rs169 rs174
> 1  1001   CC    GG     CC
> 2 10032   CC    GG     CC
> 3 10066   CC    NA     CC
>
> NA does not get assigned a missing value.
>
> Could you help me understand the logic of this. Thanks!
>   
This kind of thing doesn't travel well in email, but is is possible that
there is more than "\t" between fields?

levels(tempDat$rs169) could be illuminating.

-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
  c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
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