CODEWITHSUNDEEP
r
user1234440
user1234440

Reputation: 23587

Labeling a dotchart

Given the following example and chart, how would one be able to plot the exact value of the x axis next to each points? 

x <- mtcars[order(mtcars$mpg),] # sort by mpg
x$cyl <- factor(x$cyl) # it must be a factor
x$color[x$cyl==4] <- "red"
x$color[x$cyl==6] <- "blue"
x$color[x$cyl==8] <- "darkgreen"    
dotchart(x$mpg,labels=row.names(x),cex=.7,groups= x$cyl,
 main="Gas Milage for Car Models\ngrouped by cylinder",
   xlab="Miles Per Gallon", gcolor="black", color=x$color)

I tried modifying the labels argument, but it only adjusts the y axis label name.

Upvotes: 2

Views: 1837

Answers (1)

Gregor Thomas
Gregor Thomas

Reputation: 145965

You'll need to sort by category, then by x. Then you can use text as Ricardo suggests, accounting for the breaks between categories.

x <- mtcars[order(-mtcars$cyl, mtcars$mpg),]
# sort by category, then by position within category

# As above
x$cyl <- factor(x$cyl) # it must be a factor
x$color[x$cyl==4] <- "red"
x$color[x$cyl==6] <- "blue"
x$color[x$cyl==8] <- "darkgreen"    
dotchart(x$mpg,labels=row.names(x),cex=.7,groups= x$cyl,
         main="Gas Milage for Car Models\ngrouped by cylinder",
         xlab="Miles Per Gallon", gcolor="black", color=x$color)

# Adding text
text(x = x$mpg,
     y = 1:nrow(x) + ifelse(x$cyl == "6", 2, ifelse(x$cyl == "4", 4, 0)),
     labels= x$mpg,
     cex = 0.5,
     pos = 4)

Upvotes: 2

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