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

[Spencer Graves]

      It's apparently a unix command;  www.r-project.org -> search -> "R 
site search" -> sed produced at least one hit with the following example: 

scan(pipe("sed -e s/,$// data2"), sep=",")

      For the rest of this comment, see the R site search.  hope this 
helps.  spencer graves

Yong Wang wrote:

>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
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
>>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide!
>>http://www.R-project.org/posting-guide.html
>>
>>    
>>
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://www.stat.math.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>  
>