Reordering of legend in ggplot2

[RH12]

Dear All,

I have a follow-up question on the topic discussed below:

Adding manual legend to ggplot2

Hello, I am trying to figure out how to add a manual legend to a ggplot2 figure. From my reading, you have to add color to aes. However, from all of the examples that I have seen, the color is used for a factor variable. I have a line plot with three continuous variables. I need to add a simple legend for the colors. [51%20PM] ggplot(by_year_percentage, aes(x=arrivaldate)) + geom_line(aes(y=deathpercentage), color = "blue", size = 1.5) + geom_line(aes(y=tamponadepercentage), color = "red", size = 1.5) + geom_line(aes(y=protaminepercentage), color = "orange", size = 1.5) + labs(x="Year", y="(%)")

After manually adding a legend to my plot, as described by @andresrcs, I want to reorder the legend entries. However, I have not yet found a practicable solution.

Any advice on my issue would be highly appreciated.

[mara]

This post includes code for reordering the items in a legend:
http://www.cookbook-r.com/Graphs/Legends_(ggplot2)/

[francisbarton]

Here's an amended version of Andres's example:

library(ggplot2)

colors <- c("Petal Length" = "red", "Petal Width" = "orange", "Sepal Width" = "blue")

ggplot(datasets::iris, aes(x = Sepal.Length)) +
  geom_line(aes(y = Sepal.Width, color = "Sepal Width"), size = 1.5) +
  geom_line(aes(y = Petal.Length, color = "Petal Length"), size = 1.5) +
  geom_line(aes(y = Petal.Width, color = "Petal Width"), size = 1.5) +
  labs(x = "Year",
       y = "(%)",
       color = "Legend") +
  scale_color_manual(values = colors, breaks = names(colors)[c(3,1,2)])

^{Created on 2020-09-29 by the reprex package (v0.3.0)}

The labels default to alphabetical order I think.

[RH12]

Hi @francisbarton,

Thank you very much for your help. I just tried to implement your code, unfortunately I received the following error message:
"Removed 183 rows containing missing values (geom_path)."
Without scale_color_manual I have no problems plotting the data.

Do you have any further suggestions?

Best,

[andresrcs]

If you need more specific help, you would have to provide a REPRoducible EXample (reprex) more specific to your situation.

[RH12]

Dear @andresrcs / Francis

I tried to make a reprex (I'm a RStudio beginner) and added the output below. Although it didn't seem to have worked properly, I hope the code will help solve my problem:

#Load packages
library(tidyverse)
library(quantmod)
library(broom)
library(lubridate)

#Data Import 
start = as.Date("2020-09-25")
end = as.Date("2020-10-05")
getSymbols(c("AAPL", "AMZN", "FB", "TSLA"), src = "yahoo", from = start, to = end)

#Normalisation of data to 100 by 25 September 2020
AAPL <- ((AAPL$AAPL.Adjusted/112.28)*100)
AMZN <- ((AMZN$AMZN.Adjusted/3095.13)*100)
FB <- ((FB$FB.Adjusted/254.82)*100)
TSLA <- ((TSLA$TSLA.Adjusted/407.34)*100)

#Change formats from xts objects to data frames
AAPL <- data.frame(date = index(AAPL), coredata(AAPL))
AMZN <- data.frame(date = index(AMZN), coredata(AMZN))
FB <- data.frame(date = index(FB), coredata(FB))
TSLA <- data.frame(date = index(TSLA), coredata(TSLA))

#Merge all data frames into one dataset
merge1 <- merge(AAPL, AMZN, by = "date")
merge2 <- merge(FB, TSLA, by = "date") 
stocks <- merge(merge1, merge2, by = "date")

#Rename the dataset to avoid misunderstandings
stocks <- rename(stocks, Apple = AAPL.Adjusted, Amazon = AMZN.Adjusted, Facebook = FB.Adjusted, Tesla = TSLA.Adjusted)

#Create a legend for the plot
colors <- c("Apple" = "darkblue", "Amazon" = "gray39", "Facbeook" = "chocolate4", "Tesla" = "black")

#Plot the Data
ggplot(stocks, aes(x=date)) +
  geom_line(aes(y = Apple, color = "Apple")) +
  geom_line(aes(y = Amazon, color = "Amazon")) +
  geom_line(aes(y = Facebook, color = "Facebook")) +
  geom_line(aes(y = Tesla, color = "Tesla")) +
  scale_x_date(date_labels = "%B", date_breaks = "1 month") +
  geom_segment(aes(x = as.Date(c("2020-10-01")), y = 118, xend = as.Date(c("2020-10-01")), yend = 113), arrow = arrow(length = unit(0.25, "cm")), color = "black") +
  annotate("text", x = as.Date(c("2020-10-01")), y = 119, label = "xyz", size = 2, colour = "black") +
  geom_segment(aes(x = as.Date(c("2020-09-25")), y = 108, xend = as.Date(c("2020-09-25")), yend = 103), arrow = arrow(length = unit(0.25, "cm")), color = "black") +
  annotate("text", x = as.Date(c("2020-09-25")), y = 109, label = "xyz", size = 2, colour = "black") +
  ylab("Share Price") +
  xlab("Time Period") +
  labs(title = "Price development of selected US stocks", subtitle = "Data as of 2020-09-25 normalized to 100", caption = expression(italic("Source: Yahoo Finance (data retrieved on 2020-10-06) \nxyz")), color = "Legend") +
  theme(plot.caption = element_text(hjust = 1)) +
  theme_minimal() +
  theme(axis.title.x = element_text(margin = margin(t=10))) +
  scale_color_manual(values = colors, breaks = names(colors)[c(4,2,1,3)])

Thank you very much!

[francisbarton]

It looks OK to me. Well done. Is there anything you want to do differently?
There was just a Facebook typo in your previous example that needed fixing.

#Load packages
library(tidyverse)
library(quantmod)
library(broom)
library(lubridate)

#Data Import 
start = as.Date("2020-09-25")
end = as.Date("2020-10-05")
getSymbols(c("AAPL", "AMZN", "FB", "TSLA"), src = "yahoo", from = start, to = end)

#Normalisation of data to 100 by 25 September 2020
AAPL <- ((AAPL$AAPL.Adjusted/112.28)*100)
AMZN <- ((AMZN$AMZN.Adjusted/3095.13)*100)
FB <- ((FB$FB.Adjusted/254.82)*100)
TSLA <- ((TSLA$TSLA.Adjusted/407.34)*100)

#Change formats from xts objects to data frames
AAPL <- data.frame(date = index(AAPL), coredata(AAPL))
AMZN <- data.frame(date = index(AMZN), coredata(AMZN))
FB <- data.frame(date = index(FB), coredata(FB))
TSLA <- data.frame(date = index(TSLA), coredata(TSLA))

#Merge all data frames into one dataset
merge1 <- merge(AAPL, AMZN, by = "date")
merge2 <- merge(FB, TSLA, by = "date") 
stocks <- merge(merge1, merge2, by = "date")

#Rename the dataset to avoid misunderstandings
stocks <- rename(stocks, Apple = AAPL.Adjusted, Amazon = AMZN.Adjusted, Facebook = FB.Adjusted, Tesla = TSLA.Adjusted)

#Create a legend for the plot
colors <- c("Apple" = "darkblue", "Amazon" = "gray39", "Facebook" = "chocolate4", "Tesla" = "black")

#Plot the Data
ggplot(stocks, aes(x=date)) +
  geom_line(aes(y = Apple, color = "Apple")) +
  geom_line(aes(y = Amazon, color = "Amazon")) +
  geom_line(aes(y = Facebook, color = "Facebook")) +
  geom_line(aes(y = Tesla, color = "Tesla")) +

  scale_x_date(date_labels = "%B", date_breaks = "1 month") +
  geom_segment(aes(x = as.Date(c("2020-10-01")), y = 118, xend = as.Date(c("2020-10-01")), yend = 113), arrow = arrow(length = unit(0.25, "cm")), color = "black") +
  annotate("text", x = as.Date(c("2020-10-01")), y = 119, label = "xyz", size = 2, colour = "black") +
  geom_segment(aes(x = as.Date(c("2020-09-25")), y = 108, xend = as.Date(c("2020-09-25")), yend = 103), arrow = arrow(length = unit(0.25, "cm")), color = "black") +
  annotate("text", x = as.Date(c("2020-09-25")), y = 109, label = "xyz", size = 2, colour = "black") +
  ylab("Share Price") +
  xlab("Time Period") +
  labs(title = "Price development of selected US stocks", subtitle = "Data as of 2020-09-25 normalized to 100", caption = expression(italic("Source: Yahoo Finance (data retrieved on 2020-10-06) \nxyz")), color = "Legend") +
  theme(plot.caption = element_text(hjust = 1)) +
  theme_minimal() +
  theme(axis.title.x = element_text(margin = margin(t=10))) +
  scale_color_manual(values = colors, breaks = names(colors)[c(4,2,1,3)])

^{Created on 2020-10-06 by the reprex package (v0.3.0)}

[RH12]

@francisbarton I made a mistake in my original code where I changed something in the color values and didn't properly apply it to the whole code. Thank you very much for your help, really appreciated.

[mara]

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