Creating two separate Boxplots for yes/no variable on same plot using ggplot 2

Question

I am trying to create a boxplot where on the x axis there is a binary 1/2 variable. When I create my boxplot and the loop using ggplot I just get one big boxplot that is centered at 1.5 when instead I want a boxplot at 1 and a boxplot at 2. I am new to this so any help and additional reading would be appreciated. Below is the code.

myboxplot <- function(mydata=ivf_dataset, myexposure, myoutcome  )
  {
  bp <- ggplot(mydata, aes_(as.name(myexposure), as.name(myoutcome))) +
     geom_boxplot() 
      print(bp)
  }
 myboxplot(myexposure = "ART_CURRENT", myoutcome = "H19_DMR_mean")

See also these answers https://stackoverflow.com/a/50726130/786542 & https://stackoverflow.com/a/49870618/786542 — Tung, Jun 11 '18 at 18:29

Seymour · Answer 1 · 2018-06-11T15:57:11.163

0

myboxplot <- function(mydata=ivf_dataset, myexposure, myoutcome  )
  {
  bp <- ggplot(mydata, aes_(myexposure, as.factor(myoutcome))) +
     geom_boxplot() 
      print(bp)
  }
 myboxplot(myexposure = "ART_CURRENT", myoutcome = "H19_DMR_mean")

If you want to plot multiple boxplot based on the value of a variable, that variable must be a factor!

edited Jun 11 '18 at 15:57

answered Jun 11 '18 at 15:37

Seymour

3,104
2
22
46

Thanks for the response. Like I said, I am new at this so in order to make the variable a factor do I need to do that by modifying my dataset or is there an easy way to do it within the function? – Dillon Lloyd Jun 11 '18 at 15:49
check my answer – Seymour Jun 11 '18 at 15:57

score 0 · Accepted Answer · answered Jun 11 '18 at 15:58

0

The following will do what you want.
The trick is to get the values of the variables you want to plot, since you pass them to the function as character strings.

library(ggplot2)

set.seed(7153)
ivf_dataset <- data.frame(
  ART_CURRENT = sample.int(2, 100, TRUE),
  H19_DMR_mean = rnorm(100)
)

myboxplot <- function(mydata=ivf_dataset, myexposure, myoutcome  ){
  bp <- ggplot(mydata, aes(x = as.factor(get(myexposure)), y = get(myoutcome))) +
    geom_boxplot() 
  print(bp)
}
myboxplot(myexposure = "ART_CURRENT", myoutcome = "H19_DMR_mean")

answered Jun 11 '18 at 15:58

Rui Barradas

70,273
8
34
66

Thank you, that does work however do you have any good readings on how the "get" function works? – Dillon Lloyd Jun 11 '18 at 16:55
@DillonLloyd Well, there is `help("get")` and the source code, R is open source. But I must admit to never having read it (the source). – Rui Barradas Jun 11 '18 at 18:00

Creating two separate Boxplots for yes/no variable on same plot using ggplot 2

2 Answers2