You may want to use the reshape package for this task:
> library(reshape)
> recast(DF3,Show ~ Datetime, id.var=names(DF3),value="Measure")
Show 08/26/2009 11:30 AM 08/26/2009 9:30 AM
1 Firefly 3 1
2 Red Dwarf 4 2
If you want to plot time series, you can do something like the following
> mydf <- .Last.value ## save the output from above to mydf
> library(zoo)
> zobj <- zoo(`mode<-`(t(mydf),"numeric"),
> as.chron(strptime(names(mydf)[-1],"%m/%d/%Y %I:%M %p")))
> plot(zobj)
(zobj is a time series object of the zoo class)
----- Original Message ----
From: Tony Breyal <tony.bre...@googlemail.com>
To: r-help@r-project.org
Sent: Thursday, August 27, 2009 4:04:30 AM
Subject: [R] Merge data frames but with a twist.
Dear all,
Question: How to merge two data frames such that new column are added
in a particular way?
I'm not actually sure how to best articulate my question to be honest,
so i hope showing you what I want to achieve will communicate my
question better.
Lets say I have two data frames:
> DF1 <- data.frame(cbind(Show=c('Firefly', 'Red Dwarf'), Measure=1:2,
> Datetime=c('08/26/2009 9:30 AM', '08/26/2009 9:30 AM')))
> DF2 <- data.frame(cbind(Show=c('Firefly', 'Red Dwarf'), Measure=3:4,
> Datetime=c('08/26/2009 11:30 AM', '08/26/2009 11:30 AM')))
And then let us merge these:
> DF3 <- merge(DF1, DF2, all=TRUE)
Show Measure Datetime
1 Firefly 1 08/26/2009 9:30 AM
2 Firefly 3 08/26/2009 11:30 AM
3 Red Dwarf 2 08/26/2009 9:30 AM
4 Red Dwarf 4 08/26/2009 11:30 AM
What i would like to do is merge the data frames such that i end up
with the following:
Show 08/26/2009 9:30 AM 08/26/2009 11:30 AM
Firefly 1 3
Red Dwarf 2 4
my reason for doing this is so that i can plot a time series somehow.
I hope the formating stays when i post this message and that what i'm
trying to do is easy to understand. Thank you kindly for any help in
advance.
Tony
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
