How do I set the series labels in a multiline ggplot2 series? - r

Question

I'm currently working on automating some basic experiential analysis using R. Currently, I've got my script setup as follows which generates the plot shown below.
data <- list()
for (experiment in experiments) {
path = paste('../out/', experiment, '/', plot, '.csv', sep="")
data[[experiment]] <- read.csv(path, header=F)
}
df <- data.frame(Year=1:40,
'current'=colMeans(data[['current']]),
'vip'=colMeans(data[['vip']]),
'vipbonus'=colMeans(data[['vipbonus']]))
df <- melt(df, id.vars = 'Year', variable.name = 'Series')
plotted <- ggplot(df, aes(Year, value)) +
geom_line(aes(colour = Series)) +
labs(y = ylabel, title = title)
file = paste(plot, '.png', sep="")
ggsave(filename = file, plot = plotted)
While this is close to what we want the final product to look like, the series labels need to be updated. Ideally we want them to be something like "VIP, no bonus", "VIP, with bonus" and so forth, but obviously using labels like that in the data frame is not valid R (and invalid characters are automatically replaced with . even with backticks). Since these experiments are a work in progress, we also know that we are gong to need more series labels in the future so we don't want to lose the ability of ggplot to automatically set the colors for us.
How can I set the series labels to be appropriate for humans?

Answer 1

The OP explained that he is currently working on automating some basic experiential analysis, part of which is the relabeling of the series. The OP showed also some code which is used to prepare the data to be plotted.
Based on the additional information supplied in comments, I believe the overall processing could be streamlined which will address the series labeling issue as well.
Some preparations
# used for creating file paths
experiments <- c("current", "vip", "vipbonus")
# used for labeling the series
exp_labels <- c("Current", "VIP, no bonus", "VIP, with bonus")
plot <- "dataset1" # e.g.
paths <- paste0(file.path("../out", experiments, plot), ".csv")
paths
#[1] "../out/current/dataset1.csv" "../out/vip/dataset1.csv" "../out/vipbonus/dataset1.csv"
Read data
library(data.table) #version 1.10.4 used here
# read all files into one large data.table
# add running count in column "Series" to identify the source of each row
DT <- rbindlist(lapply(paths, fread, header = FALSE), idcol = "Series")
# rename file chunks = Series, use predefined labels
DT[, Series := factor(Series, labels = exp_labels)]
Reshape and aggregate by groups
# reshape from wide to long
molten <- melt(DT, id.vars = "Series")
# compute means by Series and Year = variable
aggregated <- molten[, .(value = mean(value)), by = .(Series, variable)]
# take factor level number of "variable" as Year
aggregated[, Year := as.integer(variable)]
Note that aggregation is done in long format (after melt()) to save typing the same command for each column.
Create chart & save to disk
library(ggplot2)
ggplot(aggregated, aes(Year, value)) +
geom_line(aes(colour = Series)) +
labs(y = "ylabel", title = "title")
file = paste(plot, '.png', sep="")
ggsave(filename = file) # by default, the last plot is saved

Answer 2

While this may not be an ideal approach, what we found that worked for us was to update the relevant series labels after the melt command was performed:
df$Series <- as.character(df$Series)
df$Series[df$Series == "current"] <- "Current"
df$Series[df$Series == "vip"] <- "VIP, no bonus"
df$Series[df$Series == "vipbonus"] <- "VIP, with bonus"
Which results in plots like the following:

Answer 3

You can try this
library(tidyverse)
df <- df %>% dplyr::mutate(Series = as.character(Series),
Series = fct_recode(Series,
"Current" = "current",
"VIP, no bonus" = "vip",
"VIP, with bonus" = "vipbonus"))