CODEWITHSUNDEEP
rggplot2
HOSS_JFL
HOSS_JFL

Reputation: 839

R: how to combine ggplots basd on data with different column names

Both ggplots below work separtely, but I would like to combine them to one plot where the Group variable of the lines in df2 appears in the legend.

library(ggplot2)
df1 <- data.frame(x = 1:10, y = 1:10)
df2 <- data.frame(x = rep(1:10,2), 
        y = c(seq(1,2,length.out = 10),
        seq(5,6,length.out = 10)), 
        Group = c(rep("A",10),rep("B",10))          
        )

p1 <- ggplot(data = df1, aes(x = x, y = y)) + 
geom_point() 

p2<- ggplot(data = df2, aes(x = x, y = y,
group = Group, color = Group)) + 
geom_line()

2 ggplots that I want to combine into 1

The problem is caused by the fact that 2 data frames have different column names. Therefore I cannot generate 2 plots and add them like p1 + p2 as it is done in other solutions that have been published here before.

Upvotes: 0

Views: 159

Answers (1)

stefan
stefan

Reputation: 124083

First, in ggplot2 each layer has its own local data argument, i.e. you could pass a different dataset to each layer. If you don't set the data argument for a layer it will simply inherit the global dataset set in ggplot() (if any), i.e. you could combine your plots into one by adding + geom_line(data = df2, aes(group = Group, color = Group)) to your first plot.

Second, if your datasets have different column names that's not a big deal either. As with the data argument, each layer has it's own (local) set of aesthetics. If not set, a layer will inherit the global aesthetics set in ggplot(), i.e. with different column names you simply have to tell which columns should be mapped on the aesthetics in each layer.

Slightly altered your example data:

library(ggplot2)
df1 <- data.frame(x1 = 1:10, y1 = 1:10)
df2 <- data.frame(x2 = rep(1:10,2), 
                  y2 = c(seq(1,2,length.out = 10),
                        seq(5,6,length.out = 10)), 
                  Group = c(rep("A",10),rep("B",10))          
)

ggplot(data = df1, aes(x = x1, y = y1)) + 
  geom_point() +
  geom_line(data = df2, aes(x = x2, y = y2, group = Group, color = Group))

Upvotes: 1

Related Questions