Thanks a lot. The code works great.
Regards
Ahmed
**********************
Ahmed Serag
Analytical Chemistry Department
Faculty of Pharmacy
Al-Azhar University
Cairo
Egypt
________________________________
From: Rui Barradas <ruipbarra...@sapo.pt>
Sent: Tuesday, May 22, 2018 2:16 PM
To: Ahmed Serag; R-help@r-project.org
Subject: Re: [R] remove rows of a matrix by part of its row name
Hello,
Please always cc the list.
As for the question, yes, it does. If you want to remove just the ones
with exactly 73.1 use the pattern
grep("^73\\.1$", etc)
Explanation:
Beginning of string: ^
End of string: $
Escape special characters: \\ (needed because the period is a special
character.)
Hope this helps,
Rui Barradas
On 5/22/2018 12:50 PM, Ahmed Serag wrote:
> Thank you Mr. Barradas. The code works great. Unfortunately I have also
> some labeles with
>
>
> 173.1
>
> 273.1
>
>
> the grep script remove them also ?
>
> Any ideas Plz, Thanks again
>
>
> ************************
>
> *Ahmed Serag*
>
> /Analytical Chemistry Department/
>
> /Faculty of Pharmacy/
>
> /Al-Azhar University/
>
> /Cairo/
>
> /Egypt/
>
>
>
> ------------------------------------------------------------------------
> *From:* Rui Barradas <ruipbarra...@sapo.pt>
> *Sent:* Tuesday, May 22, 2018 1:34 PM
> *To:* Ahmed Serag; r-help@r-project.org
> *Subject:* Re: [R] remove rows of a matrix by part of its row name
> Hello,
>
> Use grep to get the row indices and then subset with a *negative* index
> to remove those rows.
>
> rn <- scan(what = character(), text = "
> 70/556
> 71.1/280
> 72.1/556
> 72.1/343
> 73.1/390
> 73.1/556
> ")
>
> mat <- matrix(rnorm(6*6), nrow = 6)
> row.names(mat) <- rn
>
> inx <- grep("73\\.", row.names(mat))
>
> new_mat <- mat[-inx, ]
> new_mat
>
>
> Hope this helps,
>
> Rui Barradas
>
> On 5/22/2018 11:48 AM, Ahmed Serag wrote:
>> Dear R-experts,
>>
>>
>> How can I remove a certain feature or observation by a part of its name. To
>> be clear, I have a matrix with 766 observations as a rows. The row names are
>> like this
>>
>> 70/556
>> 71.1/280
>> 72.1/556
>> 72.1/343
>> 73.1/390
>> 73.1/556
>> Now I would like to remove all the rows that contain the text 73.1
>>
>> Any ideas or suggestion please ?
>>
>>
>> Regards
>>
>>
>>
>>
>> **********************
>>
>> Ahmed Serag
>>
>> Analytical Chemistry Department
>>
>> Faculty of Pharmacy
>>
>> Al-Azhar University
>>
>> Cairo
>>
>> Egypt
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
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> <https://stat.ethz.ch/mailman/listinfo/r-help>
> stat.ethz.ch
> The main R mailing list, for announcements about the development of R
> and the availability of new code, questions and answers about problems
> and solutions using R, enhancements and patches to the source code and
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>
>
>
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>>
[[alternative HTML version deleted]]
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