R help - Feb 2004 - lines and dates

Dear All,
I have the following data.frame

`data.frame':	1563 obs. of  4 variables:
 $ Model      :Class 'AsIs'  chr [1:40] "Astro"
"Astro" "Astro" "Astro"
 $ Make       :Class 'AsIs'  chr [1:40] "Chevrolet"
"Chevrolet"
 $ Production : num  11219 12384  1082  5409  5458 ...
 $ date       :`POSIXlt', format: chr  "2000-05-01"
"2000-06-01"


The data frame contains production levels of some cars from 2000 to 2003.
My question is about plotting production for  each  model.
I have a code that  outputs a plot for each model and
it works fine.  However I would like to plot couple of models together i.e
when I do

plot(temp$date, temp$Production, type="n")
by(temp, list(temp$Model), function(x) lines(x[, "date"], x[,
"Production"]))

I get an error:
      Error in xy.coords(x, y) : x and y lengths differ

I believe that it has something to do with POSIXlt. when I issue a length
or NROW command on temp$date it returns the value 9.

any help is greatly appreciated,

Jean

As per the stuff on the list earlier, it looks like you probably need to
convert the POSIXlt's to POSIXct's 
Try: 

?as.POSIXct 



-----Original Message-----
From: Jean Eid [mailto:jeaneid at chass.utoronto.ca] 
Sent: Thursday, February 05, 2004 11:39 AM
To: r-help at stat.math.ethz.ch
Subject: [R] lines and dates 


Dear All,
I have the following data.frame

`data.frame':	1563 obs. of  4 variables:
 $ Model      :Class 'AsIs'  chr [1:40] "Astro"
"Astro" "Astro" "Astro"
 $ Make       :Class 'AsIs'  chr [1:40] "Chevrolet"
"Chevrolet"
 $ Production : num  11219 12384  1082  5409  5458 ...
 $ date       :`POSIXlt', format: chr  "2000-05-01"
"2000-06-01"


The data frame contains production levels of some cars from 2000 to
2003. My question is about plotting production for  each  model. I have
a code that  outputs a plot for each model and it works fine.  However I
would like to plot couple of models together i.e when I do

plot(temp$date, temp$Production, type="n")
by(temp, list(temp$Model), function(x) lines(x[, "date"], x[,
"Production"]))

I get an error:
      Error in xy.coords(x, y) : x and y lengths differ

I believe that it has something to do with POSIXlt. when I issue a
length or NROW command on temp$date it returns the value 9.

any help is greatly appreciated,

Jean

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html