Re: [R] disaggregate frequency table into flat file

From: Charilaos Skiadas <cskiadas_at_gmail.com>
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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