CODEWITHSUNDEEP
rggplot2plot
Pratik Pandey
Pratik Pandey

Reputation: 25

How to shade an area of the curve, with values from a different column in a data table that is not part of x and y?

I have a question about shading an area in using R. I have a data table that looks like this:

enter image description here

Now, I want to plot x and y which I can do using plot(x,y, type ='l'). But the question is: How can I shade the area of the plot (from 0 to infinity in y axis) whenever my 'z' value in the data table is 1?

I really appreciate your desire to help..

Thank you so much.

Upvotes: 0

Views: 178

Answers (1)

Duck
Duck

Reputation: 39605

I would suggest next ggplot2 approach. Try creating a reference variable when z==1 so that you can identify the coordinates for x-axis and then use geom_ribbon() in next way:

library(ggplot2)
#Data
df <- data.frame(x=2:9,
                 y=(2:9)^2,
                 z=c(rep(1,5),rep(0,3)))
#Create reference
df$Ref <- ifelse(df$z==1,df$x,NA)
#Plot
ggplot(df,aes(x=x,y=y))+
  geom_line()+
  geom_ribbon(aes(x=Ref,ymin=0,ymax=Inf),fill='blue',alpha=0.4)

Output:

enter image description here

Other options would be:

#Create reference
df$Ref <- ifelse(df$z==1,df$x,NA)
df$Ref1 <- ifelse(df$z==1,1,NA)
#Option 1
ggplot(df,aes(x=x,y=y))+
  geom_line()+
  geom_ribbon(aes(x=Ref,ymin=y,ymax=Inf),fill='blue',alpha=0.4)
#Option 2
ggplot(df,aes(x=x,y=y))+
  geom_line()+
  geom_ribbon(aes(ymin=Ref1,ymax=Inf),fill='blue',alpha=0.4)

Upvotes: 0

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