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 <dwinsem...@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
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