Plotting geom_line with two columns for two categories for two years-CodePudding

I have a dataframe which looks something like below:

#sample dataframe
set.seed(42)
dates <- seq.Date(as.Date("2012-01-01"), as.Date("2013-12-30"), "day")
n <- length(dates)
dat <- data.frame(created_at = dates,
                  category = rep(LETTERS[1:2], n/2),
                  Value_A = sample(18:100, n, replace=TRUE),
                  Value_B = sample(101:200, n, replace=TRUE))

I am trying to plot the count of Value_A and Value_B for category A & B Year Wise.

I am using the following code to plot it.

#adding year column
dat <- dat %>% 
  mutate(year=lubridate::year(dat$created_at))

#plotting data
ggplot(data = dat, aes(x = created_at))  
  geom_line(aes(y = Value_A, colour = category)) 
  geom_line(aes(y = Value_B, colour = category)) 
  facet_wrap(~ year, ncol = 1, scales = "free_x")  
  labs(title = 'Value_A and Value_B Count',
       x = 'Time',
       y = 'Count')  
  theme_bw()  
  scale_x_date(date_breaks = '1 month', date_labels = "%b", expand = expansion(0,0)) 
  scale_y_log10(breaks = trans_breaks("log10", function(x) 10^x),
                labels = trans_format("log10", math_format(10^.x))) 
  theme(text=element_text(size=13),panel.spacing.x=unit(0.6, "lines"),
        panel.spacing.y=unit(1, "lines"), legend.position="bottom") 
  scale_linetype_manual(name = NULL, values = 2)

And this is how the plot looks like:

I want both Value_A & Value_B to be differentiated on color based on categories so it would make more sense.

Since I am already using colour = category in geom_line. I cannot add any specific colors.

Any guidance please?

CodePudding user response：

Instead of mapping just category on the color aes you could expand the number of categories and colors by mapping e.g. paste0(category, "_A") and paste0(category, "_B") on the color aes:

library(ggplot2)
library(scales)

ggplot(data = dat, aes(x = created_at))  
  geom_line(aes(y = Value_A, colour = paste0(category, "_A")))  
  geom_line(aes(y = Value_B, colour = paste0(category, "_B")))  
  facet_wrap(~year, ncol = 1, scales = "free_x")  
  labs(
    title = "Value_A and Value_B Count",
    x = "Time",
    y = "Count"
  )  
  theme_bw()  
  scale_x_date(date_breaks = "1 month", date_labels = "%b", expand = expansion(0, 0))  
  scale_y_log10(
    breaks = trans_breaks("log10", function(x) 10^x),
    labels = trans_format("log10", math_format(10^.x))
  )  
  theme(
    text = element_text(size = 13), panel.spacing.x = unit(0.6, "lines"),
    panel.spacing.y = unit(1, "lines"), legend.position = "bottom"
  )  
  scale_linetype_manual(name = NULL, values = 2)