[R] how to remove "." or replace it with NA?

[John Fox]

Dear Yong Wang,

When you read the data with read.table, specify the argument na.strings=".".
See ?read.table for details.

I hope that this helps,
 John

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Yong Wang
> Sent: Saturday, May 29, 2004 8:25 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] how to remove "." or replace it with NA?
> 
> Hi,all
> a quick question
> A larger file include many"." (stands for missing
> value) for variable, say, x. after
> read in the file and assign it another name such as :
> 
> x1<-data$x
> 
> but x1 is always a facotor but not numerical. 
> 
> so How can I get a numeric vector from the read in data frame.
> how can I replace those "." with "NA" to perform analysis.
> 
> thank you very much
> best regards
> 
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