Message-ID: <CAJOiR6ZjpcaXH0f0Ls+EbYpjvZGg15CaUrpySGh2R+DXJPwABg@mail.gmail.com>
Date: 2019-02-11T23:00:15Z
From: Val
Subject: Select
In-Reply-To: <7850e860f2d74c7190d81c87f9b64cb9@tamu.edu>
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 at 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 at r-project.org> On Behalf Of Val
> Sent: Monday, February 11, 2019 4:36 PM
> To: r-help at R-project.org (r-help at r-project.org) <r-help at 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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