[R] regular expression for selection

[baptiste auguie]

Hi,

Try grepl instead of sub,

mena[grepl("m5.", mena)]

HTH,

baptiste

On 14 November 2011 21:45, Petr PIKAL <petr.pikal at precheza.cz> 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?
>
> Regards
> Petr
>
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