How to get the x-axis to intercept the y-axis at zero in ggplot2-CodePudding

I have a simple line graph, that contains points less than zero on the y-axis. The x-axis is at the bottom of the graph, and thus does not intercept the y-axis at y = 0.

How can I get the x=axis to intercept at y=0 in ggplot2?

Example code:

df <- data.frame(x = 1:20, y = seq(-30, 65, by = 5))
p <- ggplot(df, aes(x, y))  
    geom_line()  
    geom_hline(yintercept = 0, linetype = "dashed", color = "blue")
p

Line graph

Many thanks in advance!

CodePudding user response：

Option 1: Limit the y-axis display with coord_cartesian

df <- data.frame(x=c(-5, 15),
                 y=c(-25, 25))
ggplot(df, aes(x,y))   
  geom_line()  
  geom_hline(yintercept = 0, linetype = "solid", color = "black")  
  coord_cartesian(ylim=c(0,50))

Option 2: Shift the xaxis label manually.

ggplot(df, aes(x,y))   
  geom_line()  
  geom_hline(yintercept = 0, linetype = "solid", color = "black")  
  theme(axis.text.x = element_text(vjust = 120))