Plot multiple lines in one graph

Question

Trying to use ggplot to plot multiple lines into one graph, but not sure how to do so with my dataset. Not sure whether I need to change the datastructure or not (transpose?)

Data looks like this:

Company   2011   2013
Company1  300    350
Company2  320    430
Company3  310    420

I also tried it transposed:

Year   Company1  Company2  Company3
2011   300       320       310 
2013   350       430       420

And for this I can plot 1 of the values using;

ggplot(data=df, aes(x=Year, y=Company1)) + geom_line(colour="red") + geom_point(colour="red", size=4, shape=21, fill="white")

But I don't know how to combine all the companies as I don't have an object 'Company' anymore to group on. Any suggestions?

Answer 1

You should bring your data into long (i.e. molten) format to use it with ggplot2:

library("reshape2")
mdf <- melt(mdf, id.vars="Company", value.name="value", variable.name="Year")

And then you have to use aes( ... , group = Company ) to group them:

ggplot(data=mdf, aes(x=Year, y=value, group = Company, colour = Company)) +
    geom_line() +
    geom_point( size=4, shape=21, fill="white")