[R] Removing a data subset

[Ivan Calandra]

Hi David,

You "just" need to learn how to subset your data.frame, see functions 
like ?subset and ?"[", as well as a good guide to understand the subtleties!

Some graphic functions also have a built-in argument to subset within 
the function (e.g. argument 'subset' in 'plot.formula'), although the 
ggplot() function doesn't seem to have it.

In any case, I would recommend you spend some time learning that aspect, 
as you will always need it in one situation or another.

HTH,
Ivan

--
Dr. Ivan Calandra
TraCEr, laboratory for Traceology and Controlled Experiments
MONREPOS Archaeological Research Centre and
Museum for Human Behavioural Evolution
Schloss Monrepos
56567 Neuwied, Germany
+49 (0) 2631 9772-243
https://www.researchgate.net/profile/Ivan_Calandra

On 29/11/2017 22:07, David Doyle wrote:
> Say I have a dataset that looks like
>
> Location    Year      GW_Elv
> MW01        1999       546.63
> MW02        1999       474.21
> MW03        1999       471.94
> MW04        1999        466.80
> MW01        2000        545.90
> MW02        2000        546.10
>
> The whole dataset is at http://doylesdartden.com/ExampleData.csv
> and I use the code below to do the graph but I want to do it without MW01.
> How can I remove MW01??
>
> I'm sure I can do it by SubSeting but I can not figure out how to do it.
>
> Thank you
> David
>
> --------------------------------------------------------------
>
> library(ggplot2)
>
> MyData <- read.csv("http://doylesdartden.com/ExampleData.csv", header=TRUE,
> sep=",")
>
>
>
> #Sets whic are detections and nondetects
> MyData$Detections <- ifelse(MyData$D_GW_Elv ==1, "Detected", "NonDetect")
>
> #Removes the NAs
> MyDataWONA <- MyData[!is.na(MyData$Detections), ]
>
> #does the plot
> p <- ggplot(data = MyDataWONA, aes(x=Year, y=GW_Elv , col=Detections)) +
>    geom_point(aes(shape=Detections)) +
>
>    ##sets the colors
>    scale_colour_manual(values=c("black","red")) + #scale_y_log10() +
>
>    #location of the legend
>    theme(legend.position=c("right")) +
>
>    #sets the line color, type and size
>    geom_line(colour="black", linetype="dotted", size=0.5) +
>    ylab("Elevation Feet Mean Sea Level")
>
> ## does the graph using the Location IDs as the different Locations.
> p + facet_grid(Location ~ .)
>
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>
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