[R] regular expression for selection

[Rainer Schuermann]

Does

library( stringr )
str_extract( mena, "m5[0-9]" )

achieve what you are looking for?

Rgds,
Rainer


On Monday 14 November 2011 10:22:09 Petr PIKAL wrote:
> Hi
> 
> > On 11/14/2011 07:45 PM, Petr PIKAL wrote:
> > > Dear all
> > > 
> > > I am again (as usual) lost in regular expression use for
> > > selection.
> 
> Here
> 
> > > are my data:
> > >> dput(mena)
> > > 
> > > c("138516_10g_50ml_50c_250utes1_m53.00-_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m54.00_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m55.00_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m56.00_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m57.00_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m58.00_s1.imp",
> > > "138516_10g_50ml_50c_250utes1_m59.00_s1.imp")
> > > 
> > > I want to select only values "m" foolowed by numbers from 53 to
> > > 59.
> > > 
> > > I used
> > > 
> > > sub("m5.", "", mena)
> > > 
> > > which correctly selects those m53 - m59 values but, in contrary
> > > to my expectation, it replaced the selected values with
> > > specified
> replacement -
> 
> > > in that case empty string.
> > > 
> > > What I shall use if I want to get rid of all but m53-m59 from
> > > those
> > > strings?
> > 
> > Hi Petr,
> > How about:
> > 
> > grep("m5",mena)
> 
> It gives numeric values which tells me that there is a match in each
> string, but as a result I need only
> 
> m53-m59 substrings.
> 
> Regards
> Petr
> 
> > Jim
> 
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