[R] Counting

Peter Ehlers ehlers at ucalgary.ca
Tue Oct 20 18:17:44 CEST 2009

```Nice solution, Bill.

-Peter Ehlers

William Dunlap wrote:
>> From: r-help-bounces at r-project.org
>> [mailto:r-help-bounces at r-project.org] On Behalf Of Peter Ehlers
>> Sent: Tuesday, October 20, 2009 8:48 AM
>> To: Ashta
>> Cc: R help
>> Subject: Re: [R] Counting
>>
>>
>>   unch <- aggregate(x2==x1, by = list(x1=x1), FUN = sum)
>>   chgd <- aggregate(x2!=x1, by = list(x1=x1), FUN = sum)
>>
>>   -Peter Ehlers
>
> When I hear 'count' I think first of the table() function.
> E.g.,
>    > d<-data.frame(x1=c(1,1,0,0,0,1,0), x2=c(1,0,1,1,0,1,1))
>    > with(d, table(x1, x1==x2))
>
>    x1  FALSE TRUE
>      0     3    1
>      1     1    2
> or
>    > with(d, table(x1, factor(x1==x2,labels=c("Changed","Unchanged"))))
>
>    x1  Changed Unchanged
>      0       3         1
>      1       1         2
> or use dimnames<- to change the labels on the table itself.
>
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
>
>> Ashta wrote:
>>> Hi All,
>>>
>>> Assume that I have the following data set  with two variables and I
>>> want count the number of observation with identical values
>> and number
>>> of time each factor changed from x1 to x2.
>>>
>>> x1  x2
>>>  1    1
>>>  1    0
>>>  0    1
>>>  0    1
>>>  0    0
>>>  1    1
>>>  0    1
>>>
>>> The output should be
>>> x1  changed
>>>                       0   3    # has changed 3 times
>>>                       1   1    # has changed 1 time
>>> x1 unchanged
>>>                       0  1    # has unchanged only 1 time
>>>                       1  2     # has unchanged 2 times
>>>
>>> Can someone help me how to do it in R?
>>>
>>> Thanks in advance
>>>
>>> ______________________________________________
>>> 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.
>>>
>>>
>> ______________________________________________
>> 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.
>>
>
>

```