R help - Jun 2025 - How to stratify data with multiple group simultaneously with R ggplot2?

?s 07:21 de 08/06/2025, Luigi Marongiu escreveu:
> I would like to plot multivariate data with ggplot2. I have multiple
> groups that I need to account for: I have the `x` and `y` values, but
> the data must be stratified also by `w` and `z`. I can group by either
> `w` or `z`, but how can I group for both simultaneously?
> In essence, in the example below, the legend should have two columns
> (A and B) and five rows (which are already there since the data is
> stratified by w). There should be 10 colors.
> How can I do that?
> Thank you
> 
>>>>>>>
> ```
> df = data.frame(x = c(rep(1,5), rep(2,5), rep(3,5), rep(4,5)),
>                                  w = rep(letters[1:5],4),
>                                  z = c(rep(LETTERS[1],10),
rep(LETTERS[2],10)),
>                                  y = rnorm(20),
>                                  stringsAsFactors = FALSE)
> library(ggplot2)
> ggplot(df, aes(x=x, y=y, colour=w, group=w)) +
>    geom_line(linewidth=2) +
>    ggtitle("A+B")
> ggplot(df[df$z=="A",], aes(x=x, y=y, colour=w, group=w)) +
>    geom_line(linewidth=2) +
>    ggtitle("A")
> ggplot(df[df$z=="B",], aes(x=x, y=y, colour=w, group=w)) +
>    geom_line(linewidth=2) +
>    ggtitle("B")
> ```
> 
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
Hello,

You can use the 4th variable to define facets. Like this?


ggplot(df, aes(x=x, y=y, colour=w)) +
   geom_line(linewidth=2) +
   facet_wrap(~ z, scales = "free_x") +
   ggtitle("A+B")


Hope this helps,

Rui Barradas



-- 
Este e-mail foi analisado pelo software antiv?rus AVG para verificar a presen?a
de v?rus.
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Thank you, facets are good but I was looking for something that could
merge everything in a single plot. I found that I could create an
additional column, say M (merge), that accommodates two parameters
into one, for instance, `a + A`, `a + B` etc. By grouping for M, I can
kind of stratify the data...

On Sun, Jun 8, 2025 at 6:03?PM Rui Barradas <ruipbarradas at sapo.pt>
wrote:
>
> ?s 07:21 de 08/06/2025, Luigi Marongiu escreveu:
> > I would like to plot multivariate data with ggplot2. I have multiple
> > groups that I need to account for: I have the `x` and `y` values, but
> > the data must be stratified also by `w` and `z`. I can group by either
> > `w` or `z`, but how can I group for both simultaneously?
> > In essence, in the example below, the legend should have two columns
> > (A and B) and five rows (which are already there since the data is
> > stratified by w). There should be 10 colors.
> > How can I do that?
> > Thank you
> >
> >>>>>>>
> > ```
> > df = data.frame(x = c(rep(1,5), rep(2,5), rep(3,5), rep(4,5)),
> >                                  w = rep(letters[1:5],4),
> >                                  z = c(rep(LETTERS[1],10),
rep(LETTERS[2],10)),
> >                                  y = rnorm(20),
> >                                  stringsAsFactors = FALSE)
> > library(ggplot2)
> > ggplot(df, aes(x=x, y=y, colour=w, group=w)) +
> >    geom_line(linewidth=2) +
> >    ggtitle("A+B")
> > ggplot(df[df$z=="A",], aes(x=x, y=y, colour=w, group=w)) +
> >    geom_line(linewidth=2) +
> >    ggtitle("A")
> > ggplot(df[df$z=="B",], aes(x=x, y=y, colour=w, group=w)) +
> >    geom_line(linewidth=2) +
> >    ggtitle("B")
> > ```
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
https://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> Hello,
>
> You can use the 4th variable to define facets. Like this?
>
>
> ggplot(df, aes(x=x, y=y, colour=w)) +
>    geom_line(linewidth=2) +
>    facet_wrap(~ z, scales = "free_x") +
>    ggtitle("A+B")
>
>
> Hope this helps,
>
> Rui Barradas
>
>
>
> --
> Este e-mail foi analisado pelo software antiv?rus AVG para verificar a
presen?a de v?rus.
> www.avg.com


-- 
Best regards,
Luigi