Thanks to everyone who contributed to my questions. As ever, I am extremely
grateful to all those on the R-list who make it what it is.

Regards

Mike Griffiths

On Tue, Nov 15, 2011 at 5:47 PM, Joshua Wiley <jwiley.psych@gmail.com>wrote:

> Hi Michael,
>
> Your strings were long so I made a bit smaller example.  Sarah made
> one good point, you want to be using gsub() not sub(), but when I use
> your code, I do not think it even works precisely for one instance.
> Try this on for size, you were 99% there:
>
> ## simplified cases
> form1 <- c('product + action * mean + CTA + help + mean * product')
> form2 <- c('product+action*mean+CTA+help+mean*product')
>
> ## what I believe your desired output is
> 'product + CTA + help'
> 'product+CTA+help'
>
> gsub("\\s\\+\\s[[:alnum:]]*\\s\\*\\s[[:alnum:]]*", "", form1)
> gsub("\\+[[:alnum:]]*\\*[[:alnum:]]*", "", form2)
>
> ## your code (using gsub() instead of sub())
> gsub("\\+*\\s*[[:alnum:]]*\\s*\\*.[[:alnum:]]", "", form1)
>
>
> ######## Running on r57586 Windows x64 ########
> > gsub("\\s\\+\\s[[:alnum:]]*\\s\\*\\s[[:alnum:]]*", "", form1)
> [1] "product + CTA + help"
> > gsub("\\+[[:alnum:]]*\\*[[:alnum:]]*", "", form2)
> [1] "product+CTA+help"
> >
> > ## your code (using gsub() instead of sub())
> > gsub("\\+*\\s*[[:alnum:]]*\\s*\\*.[[:alnum:]]", "", form1)
> [1] "product ean + CTA + help roduct"
>
> Hope this helps,
>
> Josh
>
> On Tue, Nov 15, 2011 at 9:18 AM, Michael Griffiths
> <griffiths@upstreamsystems.com> wrote:
> > Good afternoon list,
> >
> > I have the following character strings; one with spaces between the maths
> > operators and variable names, and one without said spaces.
> >
> > form<-c('~ Sentence + LEGAL + Intro + Intro / Intro1 + Intro * LEGAL +
> > benefit + benefit / benefit1 + product + action * mean + CTA + help +
> mean
> > * product')
> >
> form<-c('~Sentence+LEGAL+Intro+Intro/Intro1+Intro*LEGAL+benefit+benefit/benefit1+product+action*mean+CTA+help+mean*product')
> >
> > I would like to remove the following target strings, either:
> >
> > 1. '+ Intro * LEGAL' which is  '+ space name space * space name'
> > 2. '+Intro*LEGAL' which is  '+ nospace name nospace * nospace name'
> >
> > Having delved into a variety of sites (e.g.
> > http://www.zytrax.com/tech/web/regex.htm#search) investigating regular
> > expressions I now have a basic grasp, but I am having difficulties
> removing
> > ALL of the instances or 1. or 2.
> >
> > The code below removes just a SINGLE instance of the target string, but I
> > was expecting it to remove all instances as I have \\*.[[allnum]]. I did
> > try \\*.[[allnum]]*, but this did not work.
> >
> > form<-sub("\\+*\\s*[[:alnum:]]*\\s*\\*.[[:alnum:]]", "", form)
> >
> > I am obviously still not understanding something. If the list could offer
> > some guidance I would be most grateful.
> >
> > Regards
> >
> > Mike Griffiths
> >
> >
> >
> > --
> >
> > *Michael Griffiths, Ph.D
> > *Statistician
> >
> > *Upstream Systems*
> >
> > 8th Floor
> > Portland House
> > Bressenden Place
> > SW1E 5BH
> >
> > <
> http://www.google.com/url?q=http%3A%2F%2Fwww.upstreamsystems.com%2F&sa=D&sntz=1&usg=AFrqEzfKYfaAalqvahwrpywpJDL9DxUmWw
> >
> >
> > Tel   +44 (0) 20 7869 5147
> > Fax  +44 207 290 1321
> > Mob +44 789 4944 145
> >
> > www.upstreamsystems.com<
> http://www.google.com/url?q=http%3A%2F%2Fwww.upstreamsystems.com%2F&sa=D&sntz=1&usg=AFrqEzfKYfaAalqvahwrpywpJDL9DxUmWw
> >
> >
> > *griffiths@upstreamsystems.com <einstein@upstreamsystems.com>*
> >
> > <http://www.upstreamsystems.com/>
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > 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.
> >
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> Programmer Analyst II, ATS Statistical Consulting Group
> University of California, Los Angeles
> https://joshuawiley.com/
>



-- 

*Michael Griffiths, Ph.D
*Statistician

*Upstream Systems*

8th Floor
Portland House
Bressenden Place
SW1E 5BH

<http://www.google.com/url?q=http%3A%2F%2Fwww.upstreamsystems.com%2F&sa=D&sntz=1&usg=AFrqEzfKYfaAalqvahwrpywpJDL9DxUmWw>

Tel   +44 (0) 20 7869 5147
Fax  +44 207 290 1321
Mob +44 789 4944 145

www.upstreamsystems.com<http://www.google.com/url?q=http%3A%2F%2Fwww.upstreamsystems.com%2F&sa=D&sntz=1&usg=AFrqEzfKYfaAalqvahwrpywpJDL9DxUmWw>

*griffiths@upstreamsystems.com <einstein@upstreamsystems.com>*

<http://www.upstreamsystems.com/>

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