ggplot and R: Two variables over time

Question

I\'d like to know how to make it so that x and y, in the following example data set are plotted on the vertical axis for each element of frame in the horizontal axis. How do

Answer 1

This is a rather late answer, but if you want your frame variable intepreted date (month of the year), then convert it to a date.

You can then use scale_x_date and the scales package to format the x-axis

DF <- melt(df, id.vars = 'frame')
# note that I am arbitrarily setting each month to be the 15th 
# day of the month, to create a complete date 
DF$date <- as.Date(paste0(as.character(df$frame), '15'), '%Y%M%d')
library(scales)
ggplot(DF, aes(x =frame, y = value, colour = variable))  +  
 geom_line() + 
 scale_x_date('Month', labels = date_format('%b %Y'), breaks = date_breaks('2 months'))

Answer 2

You need to melt your data:

library(reshape2)
dfm = melt(df, id.vars='frame')
ggplot(dfm, aes(x=frame, y=value, colour=variable)) + geom_line()

This is what that does to your data frame:

> dfm
    frame variable        value
1  200912        x 0.0008923336
2  201001        x 0.0161153932
3  201002        x 0.0188150881
4  201003        x 0.0268699107
5  201004        x 0.0186573307
6  201005        x 0.0101065034
7  201006        x 0.0015441045
8  200912        y 1.3517294883
9  201001        y 0.5965402645
10 201002        y 0.6858350301
11 201003        y 0.7415458982
12 201004        y 1.0965333860
13 201005        y 0.1194482083
14 201006        y 0.1040926429