ggmosaic doesn't display the correct column names in title or x-axis

Question

I'm trying to generate multiple plots with ggmosaic using a for loop (or map) but I'm not able to pull out the correct title names or x-axis names.

This is example of the dataframe:

set.seed(42)  ## for sake of reproducibility
n <- 10
dat <- data.frame(balance=factor(paste("DM", 1:n)), 
                  credit_history=sample(c("repaid", "critical"), 10, replace = TRUE),
                  purpose=sample(c("yes", "no"), 10, replace = TRUE),
                  employment_rate=sample(c("0-1 yrs", "1-4 yrs", ">4 yrs"), 10, replace = TRUE),
                  personal_status=sample(c("married", "single"), 10, replace=TRUE),
                  other_debtors=sample(c("guarantor", "none"), 10, replace= TRUE),
                  default=sample(c("yes", "no"), 10, replace = TRUE))

library(ggmosaic)

# create a list of variables
c_names <- dat[ , c("balance", "credit_history", "purpose", "employment_rate",
                    "personal_status", "other_debtors", "default")]

for ( col in c_names ) {
  
 s<- ggplot(data = dat) +
    geom_mosaic(aes(x=product(default, col), fill = default)) +
                  ggtitle(paste("DEFAULT", col, sep = " "))
 print(s)
  }

Can someone give some advice?

Answer 1

This is probably how I would do it. Normally if you're trying to pass strings to ggplot aesthetics, you would use aes_string() and then pass all the aesthetic arguments as string values rather than as unquoted values. However, this doesn't seem to work with the product() function. The alternative I proposed below is to create a temporary data object each time where the variable on the x-axis is always x and then everything works. The title can incorporate the string without a problem.

c_names <- dat[ , c("balance", "credit_history", "purpose", "employment_rate",
                    "personal_status", "other_debtors", "default")]

for ( cn in colnames(c_names)[1:6]) {
  tmp <- data.frame(
    default =dat$default, 
    x = dat[[cn]]
  )
  s<- ggplot(data = tmp) +
    geom_mosaic(aes(x=product(default, x), fill = default)) +
    ggtitle(paste("DEFAULT", cn, sep = " "))
  print(s)
}

Answer 2

Here is a solution slightly different from that of @DaveArmstrong.

c_names <- c("balance", "credit_history", "purpose", "employment_rate",
             "personal_status", "other_debtors")

for ( col in c_names ) {
  df <- dat[, c(col, "default")]
  names(df)[1] <- "y"
  s <- ggplot(data = df) +
    geom_mosaic(aes(x=product(default, y), fill = default)) +
    ggtitle(paste("DEFAULT", col, sep = " ")) +
    labs(x=col)
  dev.new()
  print(s)
}