R 中的条形图：如何在条形图中使用空值添加条形图

Question

I want to create a barplot with in axis x 'yes' and 'no' and in axis y the variable of answers given on the question. My issue is that the dataset doesn't contain any answers with 'Yes' Therefore the bar for 'yes' is left out. Nonetheless I still want a bar for 'yes' even when the given value will be 0

# Set figure values 
a <- 1.2 # Set size of titles
b <- 1.2 # Set size of categories
c <- 1.8 # Set size of axis
d <- rgb(204/255,0,51/255) # Set the colour of the bars
e <- c(0,50) # Set the boundary for the y-axis
h <- c(0,80) # Set the boundary for the y-axis

plot(factor(df$slachtoffer.3.[df$startvraag=="Ja"]), cex = b, cex.axis = c, las=1, col = d, ylim = h, yaxt = "n", family = "Open Sans")
title(main = title[10], cex.main = a, family = "Open Sans")
axis(2, at = seq(0, 80, by = 10), las = 1, tck = -.02, cex.axis = b, family = "Open Sans")

I've also tried below but this removes the whole X axis.

plot(factor(df$slachtoffer.3.[df$startvraag=="Ja"], exclude = "N/A"), levels = c("Ja", "Nee"), labels = c("Ja", "Nee"), cex = b, cex.axis = c, las=1, col = d, ylim = h, yaxt = "n", family = "Open Sans")
title(main = title[10], cex.main = a, family = "Open Sans")
axis(2, at = seq(0, 80, by = 10), las = 1, tck = -.02, cex.axis = b, family = "Open Sans")

The data being used for the plots is plain 'yes' and 'no' answers which were given on questions during an interview. So for example: df$slachtoffer.3. is only filled with the answer 'No'. This data should only be used when the previous question df$startvraag was answered with 'yes'.

I am able to create different graphics where both 'yes' and 'no' are within the dataset. example graphic . As you can see, when there is no 'yes' available in the dataset, it just removes the whole bar instead of adding it and setting the value at 0.

So my question is: How do I create a plot where both bars: Yes and No, are visable regardless of the variable?

Answer 1

Here is a small example using packages from the tidyverse

library(tidyverse)

dat <- tibble(res = c('No', 'No', NA, "No", "No")) %>% 
  mutate(res = as.factor(res))
  
levels(dat$res) <- c(levels(dat$res),"Yes")

ggplot(dat, aes(x = res)) +
  geom_bar() +
  scale_x_discrete(drop = FALSE)