[R] grep pattern

[jim holtman]

If you want to only match names of length 6, you will have to use this pattern:

> x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ", "ZAAAAAAZ", "ZAZ",
+     "ZAAAAZAZ", "ZRITEZ")
> # match exactly values of length 6
> len6 <- "^Z[[:alpha:]]{4}Z$"
> grep(len6, x)
[1] 2 5 9
>


On Sun, May 22, 2011 at 5:10 PM, Kang Min <ngokangmin at gmail.com> wrote:
> Thanks!
>
> On May 21, 7:09 am, David Winsemius <dwinsem... at comcast.net> wrote:
>> On May 20, 2011, at 11:57 AM, Kang Min wrote:
>>
>> > Hi all,
>>
>> > I'm trying to subset a pattern in a vector. Each argument has 6
>> > letters, and I need those that start with Z and end with Z.
>>
>> > e.g.
>> > x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ")
>>
>> > I've looked up other discussions but still can't seem to find the
>> > answer.
>>
>> You may need to study the regex page a bit longer
>>
>> the "^" is the beginning of a string
>> ".+" will math can arbitrarily long string of anything
>> and "$" indicates the end of a string
>>
>>  > x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ")
>>  > grep("^Z.+Z$", x)
>> [1] 2 5
>>  > grep("^Z.+Z$", x, value=TRUE)
>> [1] "ZFHJKZ" "ZKFLPZ"
>>
>>
>>
>> > Thanks.
>> > Kangmin
>>
>> > ______________________________________________
>> > R-h... at r-project.org mailing list
>> >https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>> ______________________________________________
>> R-h... at r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?