[R] searching for a specific row name in R

[Rui Barradas]

Hello,

If you have one hundred identifier names that you want to check the 
result of

id %in% column

will have length 100, the same as length(id).
If you want a shorter result you can do

which(id %in% column)

This will give you only the TRUE values.

Hope this helps,

Rui Barradas


Às 05:16 de 14/08/2018, Deepa escreveu:
> I have a hundred identifier names that I want to check from the second
> column of a matrix with 6000 entries in the column.
> Instead of using  R > c("d", "v", "4", "s") %in% letters , is there an
> alternative?
> 
> I have the hundred identifier names that are of my interest stored in an
> array.
> 
> 
> 
> 
> On Tue, Aug 14, 2018 at 9:16 AM, Boris Steipe <boris.steipe using utoronto.ca>
> wrote:
> 
>> Use the %in% operator:
>>
>> help('%in%')
>>
>> e.g.
>>
>> R > c("d", "v", "4", "s") %in% letters
>> [1]  TRUE  TRUE FALSE  TRUE
>>
>>
>> B.
>>
>>
>>> On 2018-08-13, at 23:36, Deepa <deepamahm.iisc using gmail.com> wrote:
>>>
>>> Hi Don,
>>>
>>> When there is a list of identifier names that I want to check, the only
>> way
>>> is to loop over each entry stored in the list of identifier names or is
>>> there is there any other shortcut?
>>>
>>> Many thanks for the response?
>>>
>>> On Mon, Aug 13, 2018 at 8:18 PM, MacQueen, Don <macqueen1 using llnl.gov>
>> wrote:
>>>
>>>> Or to return a logical value, i.e., TRUE if the column contains the
>> value,
>>>> FALSE if it does not:
>>>>
>>>>   any( x[,2] == 'A501' )
>>>>
>>>> -Don
>>>> --
>>>> Don MacQueen
>>>> Lawrence Livermore National Laboratory
>>>> 7000 East Ave., L-627
>>>> Livermore, CA 94550
>>>> 925-423-1062
>>>> Lab cell 925-724-7509
>>>>
>>>>
>>>>
>>>> On 8/13/18, 12:09 AM, "R-help on behalf of Albrecht Kauffmann" <
>>>> r-help-bounces using r-project.org on behalf of alkauffm using fastmail.fm> wrote:
>>>>
>>>>     Hello Deepa,
>>>>
>>>>     sum(x[,2] == "A501")
>>>>     or
>>>>     which(x[,2] == "A501")
>>>>     .
>>>>     Best,
>>>>     Albrecht
>>>>
>>>>
>>>>     --
>>>>       Albrecht Kauffmann
>>>>       alkauffm using fastmail.fm
>>>>
>>>>     Am Mo, 13. Aug 2018, um 07:10, schrieb Deepa Maheshvare:
>>>>> Hello Everyone,
>>>>>
>>>>> I have a 1000 x 20 matrix. The second column of the matrix has the
>>>> names
>>>>> of identifiers. How do I check when a certain identifier is present
>>>> in
>>>>> the set of 1000 identifier names present in the second column. For
>>>>> instance, let the names of identifiers be A1,A2,...A1000. I want to
>>>>> check whether A501 is present .How can this be checked?
>>>>>
>>>>> Any help will be highly appreciated.
>>>>>
>>>>>
>>>>>   [[alternative HTML version deleted]]
>>>>>
>>>>> ______________________________________________
>>>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>>> 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.
>>>>
>>>>     ______________________________________________
>>>>     R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>>     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.
>>>>
>>>>
>>>>
>>>
>>>        [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>>
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>