# [R] Counting

Peter Ehlers ehlers at ucalgary.ca
Tue Oct 20 20:41:33 CEST 2009

```
Ashta wrote:
> Hi Bill and all,
>
>
> On Tue, Oct 20, 2009 at 12:09 PM, William Dunlap <wdunlap at tibco.com> 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.
>
>  This works very well for  numeric.
>  How about if the factors are character such  as F and M  (male and female) ?
>

Did you try it? Works fine for me.

-Peter Ehlers

>
>
>
>> 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?
>>>>
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>>
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