[R] Help with regular expressions

[Jim Lemon]

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 <fisher at 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
>
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