[R] regular expression

[Laurent Rhelp]

Uwe Ligges a écrit :

>
>
> Laurent Rhelp wrote:
>
>> Dear R-List,
>>
>>      I have a great many files in a directory and I would like to 
>> replace in every file the character " by the character ' and in the 
>> same time, I have to change ' by '' (i.e. the character ' twice and 
>> not the unique character ") when the character ' is embodied in "....."
>>   So, "....." becomes '.....' and ".....'......" becomes '.....''......'
>> Certainly, regular expression could help me but I am not able to use it.
>>
>> How can I do that with R ?
>
>
>
> In fact, you do not need to know anything about regular expressions in 
> this case, since you are simply going to replace certain characters by 
> others without any fuzzy restrictions:
>
> x <- "\".....'......\""
> cat(x, "\n")
> xn <- gsub('"', "'", gsub("'", "''", x))
> cat(xn, "\n")
>
>
> Uwe Ligges
>
>
>> Thank you very much
>>
>> ______________________________________________
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>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>

Yes, You are right. So I wrote the code below (that I find a little 
awkward but it works).

##-----

dirdata <- getwd()
fichnames <- list.files(path=paste(dirdata,"\\initial\\",sep=""))

for( i in 1:length(fichnames)){

      filein <- paste(dirdata,"\\initial\\",fichnames[i],sep="")
      conin <- file(filein)
      open(conin)   
      nbrows <- length( readLines(conin,n=-1) )
      close(conin)

      fileout <- paste(dirdata,"\\result\\",fichnames[i],sep="")
      conout <- file(fileout,"w")

      conin <- file(filein)
      open(conin)


      for( l in 1:nbrows )
      {
        text <- gsub('"',"'",gsub("'","''",readLines(conin,n=1)))
        writeLines(con=conout,text=text)
      }

      close(conin)
      close(conout)
  }

##------