From: Charilaos Skiadas <cskiadas_at_gmail.com>

Date: Thu, 22 May 2008 09:49:54 -0400

R-help_at_r-project.org mailing list

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. Received on Thu 22 May 2008 - 13:54:20 GMT

Date: Thu, 22 May 2008 09:49:54 -0400

On May 22, 2008, at 8:56 AM, maiya wrote:

*>
*

> sorry, my mistake!

*> the data frame should read:
**> orig<-as.data.frame.table(orig)
**> orig
**> Var1 Var2 Freq
**> 1 A A 40
**> 2 B A 5
**> 3 A B 30
**> 4 B B 25
**>
**> but basicaly i would simply like a sample of the original matrix
**> ( which is
**> a frequency table/contingency table/crosstabulation)
**>
**> hope this is clearer now!
**>
*

This should get you started:

with(list(x=sample(1:4, 10, prob=orig$Freq, replace=TRUE)), sapply (1:4, function(k) sum(x==k)))

Or you can break it up in two steps (at the cost of creating a new variable):

x <- sample(1:4, 10, prob=orig$Freq, replace=TRUE) sapply(1:4, function(k) sum(x==k))

*> maja
*

Haris Skiadas

Department of Mathematics and Computer Science
Hanover College

*>
*

> jholtman wrote:

*>>
**>> Not exactly clear what you are asking for. Your data.frame.table
**>> does not
**>> seem related to the original 'orig'. What exactly are you
**>> expecting as
**>> output?
**>>
**>> On Wed, May 21, 2008 at 10:16 PM, maiya <maja.zaloznik_at_gmail.com>
**>> wrote:
**>>
**>>>
**>>> i appologise for the trivialness of this post - but i've been
**>>> searching
**>>> the
**>>> forum wothout luck - probably simply because it's late and my
**>>> brain is
**>>> starting to go..
**>>>
**>>> i have a frequency table as a matrix:
**>>>
**>>> orig<-matrix(c(40,5,30,25), c(2,2))
**>>> orig
**>>> [,1] [,2]
**>>> [1,] 40 30
**>>> [2,] 5 25
**>>>
**>>> i basically need a random sample say 10 from 100:
**>>>
**>>> [,1] [,2]
**>>> [1,] 5 2
**>>> [2,] 0 3
**>>>
**>>> i got as far as
**>>>
**>>> orig<-as.data.frame.table(orig)
**>>> orig
**>>> Var1 Var2 Freq
**>>> 1 A A 10
**>>> 2 B A 5
**>>> 3 A B 30
**>>> 4 B B 25
**>>>
**>>> and then perhaps
**>>>
**>>> individ<-rep(1:4, times=orig$Freq)
**>>>
**>>> which gives a vector of the 100 individuals in each of the 4
**>>> groups -
**>>> cells,
**>>> but I'm
**>>> (a) stuck here and
**>>> (b) afraid this is a very round-about way at getting to what I
**>>> want i.e.
**>>> I
**>>> can now sample(individ, 10), but then I'll have a heck of a time
**>>> getting
**>>> the
**>>> result back into the original matrix form....
**>>>
**>>> sorry again, just please tell me the simple solution that I've
**>>> missed?
**>>>
**>>> thanks!
**>>>
**>>> maja
**>>>
**>>> --
**>>> View this message in context:
**>>> http://www.nabble.com/disaggregate-frequency-table-into-flat-file-
**>>> tp17396040p17396040.html
**>>> Sent from the R help mailing list archive at Nabble.com.
**>>>
**>>> ______________________________________________
**>>> R-help_at_r-project.org mailing list
**>>> https://stat.ethz.ch/mailman/listinfo/r-help
**>>> PLEASE do read the posting guide
**>>> http://www.R-project.org/posting-guide.html<http://www.r-
**>>> project.org/posting-guide.html>
**>>> and provide commented, minimal, self-contained, reproducible code.
**>>>
**>>
**>>
**>>
**>> --
**>> Jim Holtman
**>> Cincinnati, OH
**>> +1 513 646 9390
**>>
**>> What is the problem you are trying to solve?
**>>
**>> [[alternative HTML version deleted]]
**>>
*

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