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

[Yong Wang]

Samir, can you give an example for the use of sed?



On Sun, 30 May 2004, Samir Mishra wrote:

> If the data file is in text format, is large with a lot of "."s, use sed.
> It's MUCH faster than any other tool for this sort of thing.
> 
> -----Original Message-----
> From: Yong Wang [mailto:wang at galton.uchicago.edu]
> Sent: Sunday, May 30, 2004 05:25
> 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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