# [R] series of densities

David Winsemius dw|n@em|u@ @end|ng |rom comc@@t@net
Tue May 18 02:27:55 CEST 2021

```On 5/17/21 7:44 AM, Troels Ring wrote:
> Dear friends
> I'm trying to plot in silico derived values of 3 types of
> buffer-capacities  over pH values and want densities of the three
> types together at each pH with the pH values on the abscissa.
>
> I have generated some data
>
> set.seed(2345)
> pHs <- c(7.2,7.4,7.6)
> pH <- rep(pHs,each=30)
> BC <- rep(rep(c(20,10,10),each=10),3)+rnorm(90,0,5)
> type <- rep(rep(c("TOT","NC","CA"),each=10),3)
>
> ddd <- data.frame(pH,BC,type)
>
> GG <- ggplot()
> for (i in 1:3) {
>   dd <- ddd[ddd\$pH==pHs[i],]
>   GG <- GG + geom_density(data=dd,aes(x=BC,fill=type),alpha=0.1)
> }
> GG
>
> but here I only get all pH values  plotted together whereas I want 3
> series in the vertical direction at the three pH values.
>
> I wonder how this could be done?

Here are two different displays of the data. I haven't figured out what
was intended by the request for " 3 series in the vertical direction at
the three pH values".

library(ggplot2)

#violin plots are density-like

ggplot( data=ddd, aes(x=pH, y=BC,group=interaction(type,pH),
col=type))+geom_violin()

#boxplots are summary methods

ggplot( data=ddd, aes(x=pH, y=BC,group=interaction(type,pH),
col=type))+geom_boxplot()

>
> All best wishes
>
> Troels Ring, MD
> Aalborg, Denmark
>
> PS: Windows 10,
>
> R version 4.0.5 (2021-03-31
>
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```

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