scenarios when attempting to plot multiple ggplot2 layers with different scales in R
I'm experimenting with I'm sure I'm missing something obvious here, but I'm trying to create a combined plot using ggplot2 where I have two different y-axes representing different scales of measurement. My goal is to overlay a line plot on top of a bar plot, but I'm working with issues when I try to use `sec.axis` in the `scale_y_continuous` function. Here’s what I’ve attempted so far: ```r library(ggplot2) # Sample data set.seed(123) df <- data.frame(Year = rep(2020:2022, each = 2), Value1 = c(10, 15, 20, 25, 30, 35), Value2 = c(100, 150, 200, 250, 300, 350)) # Attempting to create the plot p <- ggplot(data = df, aes(x = Year)) + geom_bar(aes(y = Value1), stat = 'identity', fill = 'skyblue', position = 'dodge') + geom_line(aes(y = Value2 / 10, group = 1), color = 'red', size = 1) + scale_y_continuous(name = 'Bar Value', sec.axis = sec_axis(~.*10, name = 'Line Value')) + labs(title = 'Combined Plot with Different Scales') print(p) ``` When I run this code, I receive an behavior stating: `behavior: Invalid input: date_trans works with objects of class Date only`. It seems like it’s trying to interpret the axes incorrectly. I’ve verified that the scales I’m applying should be compatible since I'm dividing `Value2` by 10 for the line plot. I've tried adjusting the scale mappings and also experimented with different transformations, but nothing seems to resolve this. Is there a specific way I should handle dual scales when overlaying different types of plots in ggplot2? Any insights would be greatly appreciated! For context: I'm using R on Windows 11. Any pointers in the right direction?