R help - Aug 2014 - lattice scales format dates

Hello all,

Based on the help in ?xyplot, and this suggestion from another request:

http://stackoverflow.com/questions/20623041/r-formatted-auto-scaling-dat
e-axis-using-lattice

 

I was under the impression that this code should give me the desired x
axis label date format of: "1911-Jan".

 

dat  <- data.frame(var1=1:10,
date.val=as.POSIXct(seq(as.Date("1910/11/1"),
as.Date("1911/8/1"),
"months") ))

barchart(var1~date.val, data=dat, horizontal=F,
scales=list(x=list(rot=45, format="%Y-%b")))

format(dat$date.val,"%Y-%b")

________________

It doesn't. Any suggestions as to the error in my ways?

Thanks very much.

Michael Folkes

 

 


	[[alternative HTML version deleted]]

On Aug 6, 2014, at 1:11 PM, Folkes, Michael wrote:
> Hello all,
> 
> Based on the help in ?xyplot,
Which says very little about barchart in particular but rather refers you to 

?panel.barchart

It's really designed expecting  x to be a factor,
> and this suggestion from another request:
> 
> http://stackoverflow.com/questions/20623041/r-formatted-auto-scaling-dat
> e-axis-using-lattice
> 
> I was under the impression that this code should give me the desired x
> axis label date format of: "1911-Jan".
Probably would have if you were using xyplot. But barchart's author assumed
that the "x-axis" is a set of disjoint values and that's not
really how datetimes are generally considered. Try this:

 barchart(var1~factor(format(date.val, "%Y-%b")), data=dat,
horizontal=F,
          scales=list(x=list(rot=45) ) )
> 
> 
> 
> dat  <- data.frame(var1=1:10,
> date.val=as.POSIXct(seq(as.Date("1910/11/1"),
as.Date("1911/8/1"),
> "months") ))
> 
> barchart(var1~date.val, data=dat, horizontal=F,
> scales=list(x=list(rot=45, format="%Y-%b")))
> 
> format(dat$date.val,"%Y-%b")
And learn to post in plain text.
> 
> 	[[alternative HTML version deleted]]

David Winsemius
Alameda, CA, USA