[R] Substring replacement in string

[Michael Dewey]

Dear Alrik

This may seem a silly suggestion but why not just define new functions 
PMIN and PMAX to call pmin and pmax. Obviously that does not solve your 
problem if it is more general than your example.

On 28/02/2015 13:16, Alrik Thiem wrote:
> Dear Gabor,
>
> Many thanks. Works like a charm, but I can't get it to work with
>
> "pmin(pmax(pmin(a,B),pmin(a,C,d))==Y,pmax(E,e))"
>
> i.e., with strings where there're no integers following the components in the pmin/pmax functions. Could this be generalized to handle both cases?
>
> Best wishes,
> Alrik
>
> -----Ursprüngliche Nachricht-----
> Von: Gabor Grothendieck [mailto:ggrothendieck at gmail.com]
> Gesendet: Samstag, 28. Februar 2015 13:35
> An: Alrik Thiem
> Cc: r-help at r-project.org
> Betreff: Re: [R] Substring replacement in string
>
> On Fri, Feb 27, 2015 at 5:19 PM, Alrik Thiem <alrik.thiem at gmail.com> wrote:
>> I would like to replace all lower-case letters in a string that are not part
>> of certain fixed expressions. For example, I have the string:
>>
>> "pmin(pmax(pmin(x1, X2), pmin(X3, X4)) == Y, pmax(Z1, z1))"
>>
>> Where I would like to replace all lower-case letters that do not belong to
>> the functions "pmin" and "pmax" by 1 - toupper(...) to get
>>
>> "pmin(pmax(pmin(1 - X1, X2), pmin(X3, X4)) == Y, pmax(Z1, 1 - Z1))"
>>
>
> Assuming x is the input string:
>
> gsub("(\\b[a-oq-z][a-z0-9]+)", "1-\\U\\1", x, perl = TRUE)
> ## [1] "pmin(pmax(pmin(1-X1, X2), pmin(X3, X4)) == Y, pmax(Z1, 1-Z1))"
>
>
>

-- 
Michael
http://www.dewey.myzen.co.uk