[R] Grouped boxplots using ggplot() from ggplot2.

[Rolf Turner]

On 29/07/18 02:54, Jeff Newmiller wrote:

> 1) I don't know... it looks to me like you did not run my code.

Aaaarrrgghhh.  I *thought* I had, but instead left "fill=Type" inside 
the aes() call and neglected to add fill=NULL outside this call. 
Duhhhh!!! It's tough being mentally challenged, let me assure you.

> I have 
> included a complete reprex below... try it out in a fresh session. If 
> you still get the problem, check your sessionInfo package versions 
> against mine.

Yep.  Works like a charm.

> 2) This still smells like your fill parameter is inside the aes function 
> with Type as value. This causes a legend to be created, and since that 
> legend has a different name ("Type") than the colour scale, they are 
> separated. Confirm that you are using fill outside the aes function 
> (because you don't want fill to depend on the data) and have the 
> constant NULL as value (so it won't generate any fill graphical 
> representation).

Yeah.  Well.  Duhhh.  I'm a retread.
> 
> 3) I missed that... the ylim()/scales_y_continuous(breaks=) limits 
> constrain which data are included as input into the graph. The 
> coord_cartesian function forces the limits as desired.

Bewdy, ta.

> 
> 4) While showing outliers is a standard semantic feature of boxplots 
> whether produced by ggplot or lattice or base or non-R solution,

Indeed.  But the client is always right! :-)

> you can 
> please the client by making the outliers transparent.

And your code shows me how!  Which I need.  Bewdy, ta.

> There is a link to the generated image below.
> 
> ################
> # Simulate some data:
> Type <- rep( c( "National", "Local" ), each = 250 )
> M0   <- 1300+50*(0:4)
> set.seed( 42 )
> M1   <- M0 + runif( 5, -100, -50 )
> X0   <- rnorm( 250, rep( M0, each = 50 ), 150 )
> X1   <- rnorm( 250, rep( M1, each = 50 ), 100 )
> 
> library(ggplot2)
> Year <- factor( rep( 4:8, each = 50, times = 2)
>                , levels = 0:8 )
> DemoDat <- data.frame( Year = Year
>                       , Score = c( X0, X1 )
>                       , Type = Type
>                       )
> 
> ggplot( data = DemoDat
>        , aes( x = Year
>             , y = Score
>             , color = Type
>             )
>        , fill = NULL
>        ) +
>      geom_boxplot( position = position_dodge( 1 )
>                  , outlier.alpha = 0
>                  ) +
>      theme_minimal() +
>      scale_colour_manual( name = "National v. Local"
>                         , values = c( "red", "black" ) ) +
>      scale_x_discrete( drop = FALSE ) +
>      scale_y_continuous( breaks=seq( 700, 2100, 100 ) ) +
>      coord_cartesian( ylim = c( 700, 2100 ) )
> 
> # ![](https://i.imgur.com/wUVYU5H.png)

Looks perfect.  Thanks *HUGELY* for your patience with my stupidity.

<SNIP>

cheers,

Rolf

-- 
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276