[R] regular expression for selection

[Jim Lemon]

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)

Jim