Question

I would like to compare the values of two different variables in time.

For example, having two datasets:

dataset1(Date, value)
and
dataset2(Date, value)

In order to plot just first, we can execute the following:

x.Date <- as.Date(dataset1$Date)
    x <- zoo(dataset1$Value, x.Date)
    plot(x)

To the same window I would like to add (dataset2$value, dataset2$Date), and by chance set the different color.

the values dataset1$Date and dataset2$Date are not neccessary the same (some days might overlap and some not), for example dataset1$Date might contain (dec01, dec02, dec03, dec05) and dataset2$Date (dec02, dec03, dec06).

Does anyone know how to plot two (or several) time plots in the same window?

Answer 1

There are several options. Here are three options working with zoo objects.

set.seed(1)
xz = zoo(ts(rnorm(20), frequency = 4, start = c(1959, 2)))
yz = zoo(ts(rnorm(20), frequency = 4, start = c(1959, 2)))
# Basic approach
plot(xz)
lines(yz, col = "red")
# Panels
plot.zoo(cbind(xz, yz))
# Overplotted
plot.zoo(cbind(xz, yz), 
         plot.type = "single", 
         col = c("red", "blue"))

---

If you are plotting regular ts objects, you can also explore ts.plot:

set.seed(1)
x = ts(rnorm(20), frequency = 4, start = c(1959, 2))
y = ts(rnorm(20), frequency = 4, start = c(1959, 2))
ts.plot(x, y, gpars = list(col = c("black", "red")))