Question

I have a data file that looks like this:

x   ys --------------------->
1   20   25   30   12   22   12
2   12    9   12   32   12 
3   33   12   11    6    1
4    5   10   41   12    3
5    7   81   12   31    8   3   4   11

I’d like to make a scatter plot with one x value and multiple y values (ys). I was trying to use reshape with melt, but I couldn’t get the proper data structure created to make this plot. How can I do this in R and plot with ggplot? Thanks for the help.

Answer 1

So what did not work with melt? And what Problems did you have with geom_point()? Hard to say if this is what you want:

library( "reshape2" )
library( "ggplot2" )

df <- data.frame( x = rnorm(20), ya = rnorm(20), yb = rnorm(20), yc = rnorm(20) )
df <- melt(df, id.vars="x", variable.name="class", value.name="y")

ggplot( df, aes( x = x, y = y) ) +
  geom_point( aes(colour = class) )

ggplot( df, aes( x = x, y = y) ) +
  geom_point() +
  facet_wrap( "class" )