Hello,
First of all, I believe you want argument fill, not colour. In ggplot2
colour is about the border and fill about the interior.
As for the question,
1. Create a basic plot with the common aesthetics.
library(ggplot2)
pp_ALL <- iris[c(1, 5)]
names(pp_ALL) <- c("VALUE", "EXP")
p <- ggplot(data = pp_ALL, mapping = aes(x = VALUE, fill = EXP))
2. geom_density should use alpha transparency, since the densities
overlap. colour = NA removes the densities black border.
p + geom_density(alpha = 0.5, colour = NA)
3. y = ..density.. plots relative frequencies histograms, for the
default absolute frequencies or counts, comment the mapping out.
position = position_dodge() allows for extra goodies, such as to change
the space between bars, their width or to keep empty spaces when some
factor levels are missing (preserve = "single").
For the test data, with 50 elements per factor level, use a much smaller
number of bins.
Package scales has functions to display labels in percent format, there
is no need to multiply by 100.
p + geom_histogram(
mapping = aes(y = ..density..),
position = position_dodge(),
bins = 10)
p + geom_histogram(
mapping = aes(y = ..density..),
position = position_dodge(),
bins = 10) +
scale_y_continuous(labels = scales::label_percent())
Hope this helps,
Rui Barradas
Às 07:43 de 25/02/21, Bogdan Tanasa escreveu:
Thanks a lot Petr !
shall i uses "dodge" also for the RELATIVE FREQUENCY HISTOGRAMS :
p <- ggplot(iris, aes(x=Sepal.Length, y=..count../sum(..count..)*100,
colour=Species))
p+geom_histogram(position="dodge")
or is there any other way to display the RELATIVE FREQUENCY HISTOGRAMS ?
thanks again !
On Wed, Feb 24, 2021 at 11:00 PM PIKAL Petr <petr.pi...@precheza.cz> wrote:
Hi
You should use position dodge.
p <- ggplot(iris, aes(x=Sepal.Length, colour=Species))
p+geom_density()
p <- ggplot(iris, aes(x=Sepal.Length, y=..density.., colour=Species))
p+geom_histogram(position="dodge")
Cheers
Petr
-----Original Message-----
From: R-help <r-help-boun...@r-project.org> On Behalf Of Bogdan Tanasa
Sent: Wednesday, February 24, 2021 11:07 PM
To: r-help <r-help@r-project.org>
Subject: [R] overlaying frequency histograms or density plots in R
Dear all, we do have a dataframe with a FACTOR called EXP that has 3
LEVELS ;
head(pp_ALL)
VALUE EXP
1 1639742 DMSO
2 1636822 DMSO
3 1634202 DMSO
shall i aim to overlay the relative frequency histograms, or the density
histograms for the FACTOR LEVELS,
please would you let me know why the following 2 pieces of R code show
very different results :
ggplot(pp_ALL, aes(x=VALUE, colour=EXP)) + geom_density()
versus
ggplot(data=pp_ALL) +
geom_histogram(mapping=aes(x=VALUE, y=..density.., colour=EXP),
bins=1000)
thanks,
bogdan
ps : perhaps i shall email to the folks on ggplot2 mailing list too ...
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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