[R] read.csv to read output of system()?

Marianne Promberger marianne.promberger at kcl.ac.uk
Sat Dec 12 18:01:07 CET 2009

Thanks for both replies. 

Let me start by giving a better minimal example, although indeed the
regex replacement is not my problem.

system("echo \"var1,var2,var3\none,two,three\none,this is a comment,with commas.,three\" > file.csv")  

> On 12/12/09 11:02, David Winsemius wrote:
> > 
> > You need to figure out how to do multiple replacements unless it is  
> > only the first comma that you are targeting:
> > 
> >  > readLines(pipe("sed -e 's/,/;/' ~/file.csv"))
> > [1] "one;two,three"

Lovely. What I really need is read.csv and this works (with my "good
enough for the existing data; will optimize later as needed" regex):

read.csv(pipe("sed -e 's/\\( [a-zA-Z]\\+\\),/\\1;/g' file.csv"))

I can't understand that I didn't try this. I think what I tried was 
pipe( ... file.csv |") (with a Unix pipe symbol a the end)

Jon Baron <baron at psych.upenn.edu> 12-Dec-09 16:21:
> gsub(readLines("file.csv"),",",";")

Using gsub would be even neater, as it would really be self-contained
in R.

gsub("( [A-Za-z]+),","\\1;",readLines("file.csv"))

seems to work fine, but how to get this into a data frame?


Marianne Promberger PhD, King's College London
R version 2.10.0 (2009-10-26)
Ubuntu 9.04

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