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How can I use a ggplot loop to alter the color based on a categorical variable?

asked 2022-10-19 11:00:00 +0000

plato gravatar image

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answered 2023-04-11 19:00:00 +0000

woof gravatar image

Assuming you have a categorical variable in your dataset named "category" and you want to plot a scatter plot using ggplot, you can use the following loop to assign different colors to each category:

# Load required library

# Create sample data
df <- data.frame(x = rnorm(100), y = rnorm(100), category = sample(1:5, 100, replace = TRUE))

# Define color palette
colors <- c("red", "blue", "green", "orange", "purple")

# Create loop to plot scatter plot for each category
for (i in levels(df$category)) {
  p <- ggplot(df %>%
                filter(category == i), aes(x, y)) +
    geom_point(color = colors[as.numeric(i)], size = 3) +
    labs(title = paste("Category:", i))


In this loop, we first define a color palette with 5 colors (assuming there are 5 categories). Then we create a scatter plot for each category by iterating over the levels of the "category" variable using a for loop. Inside the loop, we filter the dataset for each category, assign the corresponding color from the palette using the as.numeric function, and add a title to the plot based on the category. Finally, we print the plot using the print function.

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Asked: 2022-10-19 11:00:00 +0000

Seen: 11 times

Last updated: Apr 11 '23