How to add legend with ggplot2

Question

how to add legend with ggplot2,every color represent a kind of distrbution ,data Nor_1 can download at http://pan.baidu.com/s/1dDCiTNj ,my code is as follows:

set.seed(100)
ggplot()+geom_density(aes(x=Nor_1),fill="red",color="black",size=1,alpha=0.3,adjust=1)+geom_density(aes(x=rpois(100,2)),fill=rgb(0.1,0.9,0.8),color="black",alpha=0.3,adjust=1)+geom_density(aes(x=rnbinom(100,size=0.2,mu=4)),fill="yellow",color="black",size=1,alpha=0.3,adjust=2)+geom_smooth()+coord_cartesian(xlim=c(-10,20))

enter image description here

Please provide a [reproducible example](http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) if you want to improve your chances to get help. — David Arenburg, Mar 15 '15 at 10:19
I want to get the legend like the graph shows,but my code can't do that.My code can just present a graph without the legend. — user4672728, Mar 15 '15 at 10:54
Take a look at this SO question: http://stackoverflow.com/questions/10349206/add-legend-to-ggplot2-line-plot — lawyeR, Mar 15 '15 at 11:41
I still can't work it out,Can you help me to modify my code?Thank you. — user4672728, Mar 15 '15 at 12:57

score 0 · Answer 1 · answered Mar 15 '15 at 12:42

You can add X,Y labels, title etc. using labs() function:

    dat = data.frame(a= rnorm(n = 1000,mean = 100, sd = 10), b= rnorm(n = 1000,mean = 50, sd = 10));
ggplot(dat) + geom_density(aes(a),fill="red",color="black",size=1,alpha=0.3) + 
              geom_density(aes(b),fill="blue",color="black",size=1,alpha=0.3) +
              labs(x="your X lab", y= "your Y lab", title="your title")

How to add legend with ggplot2

1 Answers1