You can either use positive lookahead/lookbehind - but support for that is a
bit flaky. Or write a proper regex, and use
backreferences to keep what you need.
R > x <- "abc 1,1 ,1 1, x,y 2,3 "
R > gsub("(\\d),(\\d)", "\\1.\\2", x, perl = TRUE)
[1] "abc 1.1 ,1 1, x,y 2.3 "
B.
> On Feb 12, 2018, at 9:34 PM, Jim Lemon <drjimle...@gmail.com> wrote:
>
> Hi Dennis,
> How about:
>
>
> # define the two values to search for
> x<-2
> y<-3
> # create your search string and replacement string
> repstring<-paste(x,y,sep=",")
> newstring<-paste(x,y,sep=".")
> # this is the string that you want to change
> thetastring<-"SIGMA(2,3)"
> sub(repstring,newstring,thetastring)
> [1] "SIGMA(2.3)"
>
> Use gsub if you want to change multiple values
>
> Jim
>
> On Tue, Feb 13, 2018 at 1:22 PM, Dennis Fisher <fis...@plessthan.com> wrote:
>> R 3.4.2
>> OS X
>>
>> Colleagues
>>
>> I would appreciate some help with regular expressions.
>>
>> I have string that looks like:
>> " ITERATION ,THETA1 ,THETA2
>> ,THETA3 ,THETA4 ,THETA5
>> ,THETA6 ,THETA7 ,SIGMA(1,1)
>> ,SIGMA(2,1) ,SIGMA(2,2)”
>>
>> In the entries that contain:
>> (X,Y) # for example, SIGMA(1,1)
>> I would like to replace the comma with a period, e.g., SIGMA(1.1) but NOT
>> the other commas
>>
>> The end-result would be:
>> " ITERATION ,THETA1 ,THETA2
>> ,THETA3 ,THETA4 ,THETA5
>> ,THETA6 ,THETA7 ,SIGMA(1.1)
>> ,SIGMA(2.1) ,SIGMA(2.2)”
>>
>> Can someone provide the regular expression code to accomplish this?
>> Thanks.
>>
>> Dennis
>>
>> Dennis Fisher MD
>> P < (The "P Less Than" Company)
>> Phone / Fax: 1-866-PLessThan (1-866-753-7784)
>> www.PLessThan.com
>>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
