[R] regular expression for selection

[Petr PIKAL]

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
>