[R] how to plot two histograms overlapped in the same plane coordinate

[Frank E Harrell Jr]

Empirical CDFs are much better for this purpose, and allow 
superpositioning (see e.g. the Ecdf function in the Hmisc package). 
Otherwise look at histbackback in Hmisc.

Frank

On 07/09/2010 11:40 AM, Andrew Miles wrote:
>
>
> I'm not sure what you are trying to do. Do you want one histogram for
> males and one for females on the same graph? If so, the simplest way to
> put two histograms together is to simply use the add parameter:
>
> age.males=age[which(sex=="M")]
> age.females=age[which(sex=="F")]
>
> hist(age.males, col="blue")
> hist(age.females, add=T)
>
> The only problem is that the hist() function does not do
> semi-transparency. I am not sure if other packages do. The code above
> will give you a blue histogram for males, and clear histogram for
> females on top of it. You'll probably have to manually alter the axes of
> the histogram to give the histograms for males and females the same
> break points (i.e. where one bar stops and another begins). See ?hist
> for more information about that.
>
> Andrew Miles
> Department of Sociology
> Duke University
>
> On Jul 9, 2010, at 9:29 AM, Mao Jianfeng wrote:
>
>> Dear R-help listers,
>>
>> I am new. I just want to get helps on how to plot two histograms
>> overlapped in the same plane coordinate. What I did is very ugly.
>> Could you please help me to improve it? I want to got a plot with semi-
>> transparent overlapping region. And, I want to know how to specify the
>> filled colors of the different histograms.
>>
>> I also prefer other solutions other than ggplot2.
>>
>> Many thanks to you.
>>
>>
>> What I have done:
>>
>> library(ggplot2)
>>
>> age<-c(rnorm(100, 1.5, 1), rnorm(100, 5, 1))
>> sex<-c(rep("F",100), rep("M", 100))
>> mydata<-cbind(age, sex)
>> mydata<-as.data.frame(mydata)
>> head(mydata)
>>
>>
>> qplot(age, data=mydata, geom="histogram", fill=sex, xlab="age",
>> ylab="count", alpha=I(0.5))
>>
>>
>> Best,
>>
>>
>> Mao J-F
>>
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>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Frank E Harrell Jr   Professor and Chairman        School of Medicine
                      Department of Biostatistics   Vanderbilt University