[R] Calculating differences

[Jeffrey Joh]

Great!  Thank you!

 

With the data, I would like to make a scatter plot with speed on the x-axis and C differences on the y-axis, with a different color to represent different dates.  There are over 50 different dates, so I want 50 different colors on a single plot.  How can I make this plot?

 

If I wanted to make 50 separate plots for 50 different dates, how can I do that?

 

Jeffrey

 



----------------------------------------
> Date: Thu, 20 Oct 2011 17:39:42 -0700
> Subject: Re: [R] Calculating differences
> From: djmuser at gmail.com
> To: johjeffrey at hotmail.com
> CC: r-help at r-project.org
>
> Hi:
>
> Here's one way with the plyr package. Using ds as the name of your
> data frame (thank you for the dput and clear description of what you
> wanted, BTW),
>
> library('plyr')
> ddply(ds, .(date), mutate, minspd = min(speed), Cmin =
> C[which.min(speed)], diff = C - Cmin)
> speed C house date hour id minspd Cmin diff
> 1 3 0.697 1 719 18 1000 3 0.697 0.000
> 2 9 0.011 1 1027 8 10000 4 0.015 -0.004
> 3 4 0.015 1 1027 8 10001 4 0.015 0.000
> 4 8 0.012 1 1027 8 10002 4 0.015 -0.003
> 5 7 0.018 1 1030 11 10003 6 0.019 -0.001
> 6 6 0.019 1 1030 11 10004 6 0.019 0.000
>
> HTH,
> Dennis
>
> On Thu, Oct 20, 2011 at 2:56 PM, Jeffrey Joh <johjeffrey at hotmail.com> wrote:
> >
> > I have a table that looks like this:
> >
> > structure(list(speed = c(3,9,4,8,7,6), C = c(0.697, 0.011, 0.015, 0.012, 0.018, 0.019), house = c(1,
> > 1, 1, 1, 1, 1), date = c(719, 1027, 1027, 1027, 1030, 1030),
> > hour = c(18, 8, 8, 8, 11, 11), id = c("1000", "10000",
> > "10001", "10002", "10003", "10004")), .Names = c("speed",
> > "C", "house", "date", "hour", "id"), class = "data.frame", row.names = c("1000",
> > "10000", "10001", "10002", "10003", "10004"))
> >
> > I want to determine the minimum speed for each date, and the C that corresponds to that lowest speed.Then I want to make a table that contains all speeds and the difference between C and the lowest C.
> >
> > For example, on the date 1027, the minimum speed is 4 and the C that corresponds to that is 0.015. The new table should contain:
> > speed 8 and C -0.003
> > speed 9 and C -0.004
> > speed 7 and C -0.001How do you do this?
> >
> > Thanks,
> > Jeffrey
> >
> > [[alternative HTML version deleted]]
> >
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