[R] Select

[Jeff Newmiller]

This constraint was not clear in your original sample data set. Can you expand the data set to clarify how this requirement REALLY works?

On February 11, 2019 3:00:15 PM PST, Val <valkremk using gmail.com> wrote:
>Thank you David.
>
>However, this will not work for me. If the group ID selected then all
>of its observation should be included.
>
>On Mon, Feb 11, 2019 at 4:51 PM David L Carlson <dcarlson using tamu.edu>
>wrote:
>>
>> First expand your data frame into a vector where G1 is repeated 25
>times, G2 is repeated 15 times, etc. Then draw random samples of 40
>from that vector:
>>
>> > grp <- rep(mydat$group, mydat$count)
>> > grp.sam <- sample(grp, 40)
>> > table(grp.sam)
>> grp.sam
>> G1 G2 G3 G4 G5
>> 10  9  5 13  3
>>
>> ----------------------------------------
>> David L Carlson
>> Department of Anthropology
>> Texas A&M University
>> College Station, TX 77843-4352
>>
>>
>> -----Original Message-----
>> From: R-help <r-help-bounces using r-project.org> On Behalf Of Val
>> Sent: Monday, February 11, 2019 4:36 PM
>> To: r-help using R-project.org (r-help using r-project.org)
><r-help using r-project.org>
>> Subject: [R] Select
>>
>> Hi all,
>>
>> I have a data frame  with tow variables  group and its size.
>> mydat<- read.table( text='group  count
>> G1 25
>> G2 15
>> G3 12
>> G4 31
>> G5 10' , header = TRUE, as.is = TRUE )
>>
>> I want to select   group ID randomly (without replacement)  until 
>the
>> sum of count reaches 40.
>> So, in  the first case, the data frame could be
>>    G4 31
>>    65 10
>>
>> In other case, it could be
>>   G5 10
>>   G2 15
>>   G3 12
>>
>> How do I put sum of count variable   is  a minimum of 40 restriction?
>>
>> Than k you in advance
>>
>>
>>
>>
>>
>>
>> I want to select group  ids randomly until I reach the
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
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>> 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.

-- 
Sent from my phone. Please excuse my brevity.