R help - Jul 2015 - ggplot2 - Specifying Colors Manually

Hi,

Given a data frame, I'm trying to graph multiple lines on one graph, each
line being a different color and each colored line corresponding to a
specific name in the legend. Here is a very basic data sample to work with:

 x <- seq(0,40,10)
 y1 <- sample(1:50,5)
 y2 <- sample(1:50,5)

 mydf <- data.frame(x,y1,y2)

 p <- ggplot(mydf,aes(x=mydf$x)) +
geom_line(aes(y=mydf$y1,colour="green4")) +
geom_line(aes(y=mydf$y2,colour="blue2"))  +

 scale_color_manual(name="legend",values=c(y1="green4",y2="blue2"))


 p


When I run this, the entire plot is blank. What I WANT to show up is two
lines, one being the color of green4 and the other being blue2. Besides
that, I'm trying to associate the colors with the names "y1" and
"y2" in
the legend, but my codes don't seem to be working.

I'm very new to R/ggplot2, and I really appreciate any and all help I can
get.

Thank you!

	[[alternative HTML version deleted]]

Try this:

ggplot(mydf,aes(x)) +
  geom_line(aes(y = y1, colour = "y1")) +
  geom_line(aes(y = y2, colour = "y2"))  +
  scale_color_manual(values = c(y1 = "green4", y2 =
"blue2"))

Note that you don't need to use `mydf` and names in the manual scale
should match the values in the aes() calls.
Alsoit'smucheasiertoreadyourcodeifyouusespaces;)

Hadley

On Wed, Jul 22, 2015 at 1:13 PM, Abiram Srivatsa <avsrivatsa at gmail.com>
wrote:
> Hi,
>
> Given a data frame, I'm trying to graph multiple lines on one graph,
each
> line being a different color and each colored line corresponding to a
> specific name in the legend. Here is a very basic data sample to work with:
>
>  x <- seq(0,40,10)
>  y1 <- sample(1:50,5)
>  y2 <- sample(1:50,5)
>
>  mydf <- data.frame(x,y1,y2)
>
>  p <- ggplot(mydf,aes(x=mydf$x)) +
> geom_line(aes(y=mydf$y1,colour="green4")) +
> geom_line(aes(y=mydf$y2,colour="blue2"))  +
>
> 
scale_color_manual(name="legend",values=c(y1="green4",y2="blue2"))
>
>
>  p
>
>
> When I run this, the entire plot is blank. What I WANT to show up is two
> lines, one being the color of green4 and the other being blue2. Besides
> that, I'm trying to associate the colors with the names "y1"
and "y2" in
> the legend, but my codes don't seem to be working.
>
> I'm very new to R/ggplot2, and I really appreciate any and all help I
can
> get.
>
> Thank you!
>
>         [[alternative HTML version deleted]]
>
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