Question
Answer and Explanation
When using ggpairs from the GGally package in R, you may encounter numbers displayed in the upper triangle of the plot matrix. These numbers usually represent correlation coefficients. If you want to remove these numbers, you can customize the ggpairs function using a custom function in the upper argument.
Here's how you can do it:
1. Load the Necessary Packages:
- Make sure you have GGally and ggplot2 installed and loaded.
2. Create a Custom Upper Function:
- You'll create a function that returns an empty plot. This replaces the default behavior of showing correlation values. This function will be applied to the upper triangle of the ggpairs matrix.
3. Use the Custom Function in ggpairs:
- You will pass this custom function to the upper argument of ggpairs.
4. Example Code:
Here is the R code to achieve that:
# Load libraries
library(GGally)
library(ggplot2)
# Create a sample dataframe
data <- data.frame(x = rnorm(100), y = rnorm(100), z = rnorm(100))
# Custom function to remove numbers
no_num_upper <- function(data, mapping){
ggplot(data = data, mapping = mapping) +
geom_blank() +
theme_void()
}
# Create ggpairs plot without numbers in upper triangle
ggpairs(data, upper = list(continuous = no_num_upper))
Explanation:
- The no_num_upper function creates an empty plot using geom_blank() and then removes any surrounding aesthetics using theme_void(). This will result in an empty plot for each cell in the upper triangle of ggpairs output.
- We specify the upper argument to use the custom function using list(continuous = no_num_upper), ensuring this only applies to continuous variables.
Additional Customization:
- If you need to customize other parts of the ggpairs output (e.g., lower triangle, diagonal), you can pass similar custom functions to the lower and diag arguments respectively.
By using this method, you can effectively remove the correlation numbers from the upper triangle of your ggpairs plot in R while retaining the other aspects of the visualization.