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

[Samir Mishra]

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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