geom_line ggplot2中同一组的两个不同图例

Question

I want to plot two variables of the same groups, but I need that they are present in two separated legends, one for each variable (solid and dashed line) Because they share the same group, ggplot is showing them in the same legend.

The code below reproduces my problem.

df = data.frame(
  group_ = c("A","A","A","A","A","B","B","B","B","B"),
  var1 = c(1:10),
  var2 = c(11:20),
  x_ = c(1:5))


ggplot(data=df , group = a)+
  geom_line(aes(x= x_, y=var1, color= group_))+
  geom_line(aes(x= x_, y=var2, color= group_), lty=2)

Answer 1

You can try reshaping your data frame to allow you to set color aes to group and linetype aes to the variable type.

library(reshape2)
df2 <- melt(df, id.vars=c("x_", "group_"))

ggplot(data=df2)+
  geom_line(aes(x= x_, y=value, color= group_, lty=variable))