[R] using "aggregate" when variable names contain spaces

[David Winsemius]

On Apr 18, 2011, at 3:40 PM, Dimitri Liakhovitski wrote:

> That's helpful, thanks! Unfortunately, I cannot refer to all of my
> variables to the left of tilda one by one - I have a lot of them.
> Any way to get them in as a a bunch (somehow using mynames)?

fmla <- as.formula(paste(
      paste("`", names(example)[2:3], "`", sep="", collapse="+"),
      "~group+mydate")    )

aggregate(fmla, sum,data=example)

> Thanks!
>
> On Mon, Apr 18, 2011 at 3:34 PM, David Winsemius <dwinsemius at comcast.net 
> > wrote:
>>
>> On Apr 18, 2011, at 3:19 PM, Dimitri Liakhovitski wrote:
>>
>>> Hello!
>>>
>>> my data set has many variables. Unfortuantely, many of those  
>>> variables
>>> contain spaces in their names.
>>> I need advice on: how to refer to variable names in the formula for
>>> "aggregate". See example below:
>>>
>>> ### Generating example data set:
>>> mydate = rep(seq(as.Date("2008-12-01"), length = 3, by = "month"),4)
>>> value1=c(1,10,100,2,20,200,3,30,300,4,40,400)
>>> value2 
>>> =c(1.1,10.1,100.1,2.1,20.1,200.1,3.1,30.1,300.1,4.1,40.1,400.1)
>>> example<-data.frame(mydate=mydate,value1=value1,value2=value2)
>>>
>>> example$group<-c(rep("group1",3),rep("group2",3),rep("group1", 
>>> 3),rep("group2",3))
>>> exampe$group<-as.factor(exampe$group)
>>>
>>> ### Generating variable names with spaces:
>>> names(example)<-c("mydate", "my value 1","my value 2","group")
>>>
>>> ### Trying to aggregate - but it's not working. Clearly, my  
>>> reference
>>> to variable names is incorrect:
>>> mynames<-names(example)
>>> example.agg1<-aggregate(cbind(mynames)~group 
>>> +mydate,sum,data=example)
>>
>> Use backticks:
>>
>>> aggregate(`my value 1` + `my value 2` ~group 
>>> +mydate,sum,data=example)
>>   group     mydate `my value 1` + `my value 2`
>> 1 group1 2008-12-01                         8.2
>> 2 group2 2008-12-01                        12.2
>> 3 group1 2009-01-01                        80.2
>> 4 group2 2009-01-01                       120.2
>> 5 group1 2009-02-01                       800.2
>> 6 group2 2009-02-01                      1200.2
>>>
>>
>>
>> --
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>>
>
>
>
> -- 
> Dimitri Liakhovitski
> Ninah Consulting
> www.ninah.com

David Winsemius, MD
West Hartford, CT