R ggplot2 - 在同一图中绘制年份变量

Question

How do I plot each year as a separate line in ggplot2 I tried the below code but it seems to plot continuous as a single plot.

library(ggplot2)

# Dummy data
data <- data.frame(
  Date = c(as.Date("2017-01-14") - 0:13,as.Date("2016-01-14") - 0:13),
  value = runif(28) 
)
#data$Date <- strptime(data$Date, "%Y-%m-%d" )
data$Year <- as.character(year(data$Date))
data$Year <- factor(data$Year)

ggplot(data) + geom_line(aes(x = Date, y = value, group=Year, color=Year)) +
  scale_x_date(date_breaks = "1 day", date_labels = "%d-%m-%y") +
  theme(axis.text.x = element_text(angle = 90))

But I want each year to be a separate graph in the same plot.

something like below

Answer 1

Try this approach formating day and month in your date. You got a mess in your plot because of the different year in your date variable. Setting format can help you. Here the code:

library(ggplot2)
library(lubridate)
# Dummy data
data <- data.frame(
  Date = c(as.Date("2017-01-14") - 0:13,as.Date("2016-01-14") - 0:13),
  value = runif(28) 
)
data$Year <- as.character(year(data$Date))
data$Year <- factor(data$Year)
#Format month
data$MonthDay <- format(data$Date,'%b-%d')
#Plot
ggplot(data) + geom_line(aes(x = MonthDay, y = value, group=Year, color=Year)) +
  theme_bw()+
  theme(axis.text.x = element_text(angle = 90))

Output: