Re: [R] regular expression for selection

[Uwe Ligges]

On 14.11.2011 10:22, 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.

gsub(".*_(m5.).*", "\\1", mena)

Uwe Ligges

Regards
Petr

Jim

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