ggplot2: how to show the legend
ggplot2, r
Solution
In `ggplot2`, legends are shown for every aesthetic (`aes`) you set; such as `group`, `colour`, `shape`. And to do that, you'll have to get your data in the form:
A variable value
1 res1 11
... ... ...
6 res1 85
7 res2 75
You can accomplish this with `reshape2` using `melt` (as shown below):
require(reshape2)
require(ggplot2)
ggplot(dat = melt(df, id.var="A"), aes(x=A, y=value)) +
geom_line(aes(colour=variable, group=variable)) +
geom_point(aes(colour=variable, shape=variable, group=variable), size=4)
For example, if you don't want `colour` for points, then just remove `colour=variable` from `geom_point(aes(.))`. For more legend options, follow `this link`.
Problem
I made a simple classic plot with `ggplot2` which is two graphs in one. However, I'm struggling in showing the legend. It's not showing the legend. I didn't use the melt and reshape way, I just use the classic way. Below is my code. ``` df <- read.csv("testDataFrame.csv") graph <- ggplot(df, aes(A)) + geom_line(aes(y=res1), colour="1") + geom_point(aes(y=res1), size=5, shape=12) + geom_line(aes(y=res2), colour="2") + geom_point(aes(y=res2), size=5, shape=20) + scale_colour_manual(values=c("red", "green")) + scale_x_discrete(name="X axis") + scale_y_continuous(name="Y-axis") + ggtitle("Test") #scale_shape_discrete(name ="results",labels=c("Res1", "Res2"),solid=TRUE) print(graph) ``` the data frame is: ``` A,res1,res2 1,11,25 2,29,40 3,40,42 4,50,51 5,66,61 6,75,69 7,85,75 ``` Any suggestion on how to show the legend for the above graph?