v@|kremk @end|ng |rom gm@||@com
Tue Feb 12 00:31:27 CET 2019
Sorry Jeff and David for not being clear!
The total sample size should be at least 40, but the selection should
be based on group ID. A different combination of Group ID could give
at least 40.
If I select group G1 with 25 count and G2 and with 15 counts
then I can get a minimum of 40 counts. So G1 and G2 are
In another scenario, if G2, G3 and G4 are selected then the total
count will be 58 which is greater than 40. So G2 , G3 and G4 could
So the restriction is to find group IDs that give a minim of 40.
Once, I reached a minim of 40 then stop selecting group and output
I am hope this helps
On Mon, Feb 11, 2019 at 5:09 PM Jeff Newmiller <jdnewmil using dcn.davis.ca.us> wrote:
> 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>
> >> 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
> >> 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
> >> ______________________________________________
> >> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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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
> >PLEASE do read the posting guide
> >and provide commented, minimal, self-contained, reproducible code.
> Sent from my phone. Please excuse my brevity.
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