How to put legend names in numerical order

March 3, 2022

I am working with strings that end with a number and would like to put the strings in numerical order for the figure legend.

# Example dataframe
d <- data.frame(
  SampleID = sprintf("sample_%s", rep(10:39)),
  Variable = 1:30,
  Group = append(rep("group_1", each = 15), rep("group_2", each = 15)),
  Group1 = runif(30, min=0, max=100),
  Group2 = runif(30, min=0, max=100)
)

# Character level I add to give each animal unique shape
d$Animals <- sprintf("Animal_%s",rep(c(1:10), each = 3)) 

library(ggplot2)

# Plot
ggplot(d, aes(Group1, Group2, color=Group, shape=Animals)) +
  xlab(paste0("Value 1")) +
  ylab(paste0("Value 2")) + 
  coord_fixed() +
  geom_point() +
  scale_shape_manual(values=c(0:10))

My current output is this

>Solution :

You can make the convert the Animal variable into an ordered and leveled factor

# Example dataframe
d <- data.frame(
  SampleID = sprintf("sample_%s", rep(10:39)),
  Variable = 1:30,
  Group = append(rep("group_1", each = 15), rep("group_2", each = 15)),
  Group1 = runif(30, min=0, max=100),
  Group2 = runif(30, min=0, max=100)
)

# Character level I add to give each animal unique shape
d$Animals <- sprintf("Animal_%s",rep(c(1:10), each = 3)) 


d <- d %>% 
  mutate(Animals = factor(Animals, 
                          levels = c( "Animal_1" , "Animal_2" , "Animal_3" , "Animal_4",  "Animal_5" ,
  "Animal_6" , "Animal_7",  "Animal_8" , "Animal_9"  ,"Animal_10"), 
  ordered = T))
library(ggplot2)

# Plot
ggplot(d, aes(Group1, Group2, color=Group, shape=Animals)) +
  xlab(paste0("Value 1")) +
  ylab(paste0("Value 2")) + 
  coord_fixed() +
  geom_point() +
  scale_shape_manual(values=c(0:10))