Is there an equivalent in ggplot to the varwidth option in plot?

Question

I am creating boxplots using ggplot and would like to represent the sample size contributing to each box. In the base plot function there is the varwidth

Answer 1

The current versions of ggplot2 (V 2.1.0) now contains a varwidth option:

data <- data.frame(rbind(cbind(rnorm(700, 0,10), rep("1",700)),
                     cbind(rnorm(50, 0,10), rep("2",50))))
data$X1 <- as.numeric(as.character(data$X1))
ggplot(data = data, aes(x = X2, y = X1)) + 
    geom_boxplot(varwidth = TRUE) 

Answer 2

Not elegant but you can do that by:

data <- data.frame(rbind(cbind(rnorm(700, 0,10), rep("1",700)),
                         cbind(rnorm(50, 0,10), rep("2",50))))
data[ ,1] <- as.numeric(as.character(data[,1]))
w <- sqrt(table(data$X2)/nrow(data))
ggplot(NULL, aes(factor(X2), X1)) + 
  geom_boxplot(width = w[1], data = subset(data, X2 == 1)) +
  geom_boxplot(width = w[2], data = subset(data, X2 == 2))

If you have several levels for X2, then you can do without hardcoding all levels:

ggplot(NULL, aes(factor(X2), X1)) + 
  llply(unique(data$X2), function(i) geom_boxplot(width = w[i], data = subset(data, X2 == i)))

Also you can post a feature request: https://github.com/hadley/ggplot2/issues