Group data and plot multiple lines

Question

I\'d like to plot multiple lines in R for this dataset: (x = Year, y = Value)

School_ID   Year    Value
A           1998    5
B           1998    10
C                


        

Answer 1

Is this what you want? You need group = School_id to tell ggplot2 to plot separate lines for each school. If you want the horizontal axis to incluude all years between 1998 and 2005, then remove factor in x = factor(year)

  library(ggplot2)

df = read.table(text = "School_id Year Value 
 A           1998    5
 B           1998    10
 C           1999    15
 A           2000    7
 B           2005    15", sep = "", header = TRUE)

ggplot(data = df, aes(x = factor(Year), y = Value, color = School_id)) +       
  geom_line(aes(group = School_id)) + geom_point()