Diagramm zwei Variablen
ggplot(test_data, aes(date)) +
geom_line(aes(y = var0, colour = "var0")) +
geom_line(aes(y = var1, colour = "var1"))
Fragile Finch
ggplot(test_data, aes(date)) +
geom_line(aes(y = var0, colour = "var0")) +
geom_line(aes(y = var1, colour = "var1"))