ggplot a dataframe with a matrix variable?-CodePudding

I am trying to replicate this plot using ggplot

pacman::p_load(tidyverse, pls, remotes)
install_github("rwehrens/ChemometricsWithR")

data(gasoline)
wavelengths <- seq(900,1700, 2)
matplot(wavelengths, t(gasoline$NIR), type = "l", lty = 1, xlab = "Wavelength (nm)", ylab = "1/R")

but cannot seem to make it work. The gasoline dataset is a tricky one: one of the two variables is a matrix which I have never encountered before. How can I clean up this dataset to make it tidy? I tried the following:

gasoline2 <- as.data.frame(as.matrix(gasoline)) %>% 
  pivot_longer(cols = -c(octane),
              names_to = "wavelength",
              values_to = "1/R")

but cannot seem to This code:

ggplot(gasoline, mapping = aes(x = wavelengths, y = t(gasoline$NIR))) 
  geom_line(mapping = aes(color = octane))

is returning this error:

Error in `geom_line()`:
! Problem while computing aesthetics.
ℹ Error occurred in the 1st layer.
Caused by error in `check_aesthetics()`:
! Aesthetics must be either length 1 or the same as the data (60)
✖ Fix the following mappings: `x` and `y`
Backtrace:
  1. base (local) `<fn>`(x)
  2. ggplot2:::print.ggplot(x)
  4. ggplot2:::ggplot_build.ggplot(x)
  5. ggplot2:::by_layer(...)
 12. ggplot2 (local) f(l = layers[[i]], d = data[[i]])
 13. l$compute_aesthetics(d, plot)
 14. ggplot2 (local) compute_aesthetics(..., self = self)
 15. ggplot2:::check_aesthetics(evaled, n)

CodePudding user response：

The answer that

CodePudding user response：

pacman::p_load(tidyverse, pls, remotes)
install_github("rwehrens/ChemometricsWithR")

gasoline2 <- as.data.frame(as.matrix(gasoline)) %>% 
  pivot_longer(cols = -c(octane),
              names_to = "wavelength",
              values_to = "1/R") %>% 
  mutate(wavelength = str_remove_all(wavelength, "[^[:digit:]]"))

ggplot(gasoline2, mapping = aes(x = wavelength, y = `1/R`)) 
  geom_line(mapping = aes(color = octane))

** However, I can not figure out the scale_color_gradient syntax to match the colors

Edit: Thanks to the previous two posters here is my final replica!

gasoline2 <- as.data.frame(as.matrix(gasoline)) %>% 
  mutate(group = row_number()) %>%
  relocate(group, .after = octane) %>% 
  pivot_longer(cols = -c(octane, group),
              names_to = "wavelength",
              values_to = "spectra") %>% 
  mutate(wavelength = as.numeric(str_remove_all(wavelength, "[^[:digit:]]"))) %>% 
  mutate(octane = as.factor(octane))

ggplot(gasoline2, mapping = aes(x = wavelength, y = `1/R`, color = octane, group = group)) 
  geom_line(linewidth = 0.5) 
  scale_color_discrete(guide = "none") 
  xlab(label = "\nWavelength (nm)") 
  ylab(label = "1/R\n") 
  theme_classic() 
  scale_y_continuous(n.breaks = 7) 
  scale_x_continuous(breaks = seq(1000,1600,200))