错误：美学必须是长度1或与数据相同（n）：填充

Question

I want to add a line (from the data of a second dataframe) to the plot of a first dataframe. Here they are:

Year<-c(rep(2001,5),rep(2002,5),rep(2003,5),rep(2004,5),rep(2005,5))
name<-c("John","Ellen","Mark","Randy","Luisa")
Name<-c(rep(name,5))
Value<-sample(seq(0,25,by=1),25)
mydata<-data.frame(Year,Name,Value)

Year_2<-c(2001:2005)
Value_2<-c(1,0,10,3,7)
mydata_2<-data.frame(Year_2,Value_2)

This is the plot I want to obtain from the first dataframe:

plot<-ggplot(mydata, aes(fill=Name, y=Value, x=Year)) +
  geom_bar(position="stack", stat="identity") + 
  scale_color_viridis(discrete = TRUE)+
  scale_fill_viridis(discrete = TRUE) +
  theme(axis.line = element_blank(),
        axis.text.x=element_text(size=11,margin=margin(b=10)),
        axis.text.y=element_text(size=11,margin=margin(l=10)),
        axis.ticks.y = element_blank(),
        axis.title=element_text(size=18,face="bold"),
        panel.grid.major = element_blank(), panel.grid.minor = element_blank(),
        panel.background = element_blank(),
        legend.text = element_text(size=14,face = "italic"),
        legend.title = element_text(size=18))

And I tried to add the line from the second dataframe, in this way:

plot +  geom_line(data=mydata_2, size=1, aes(x=Year_2,y=Value_2))

Getting this error, which I do not really understand:

Error: Aesthetics must be either length 1 or the same as the data (5): fill

I guess it's because mydata is of length 25 and mydata_2 is 5. But what does fill has to do with this? Actually, inserting a fill argument partially solves the problem:

plot +  geom_line(data=mydata_2, size=1, aes(x=Year_2,y=Value_2,fill="red"))

Now the plot has the desired line, but I cannot seem to adjust the aesthetic of the line itself (eg the colour, that is actually black and not red, or other parameters I tried to add). Anyway, I tried adjusting the length of mydata_2 :

Year_3<-c(rep(2001,5),rep(2002,5),rep(2003,5),rep(2004,5),rep(2005,5))
Value_3<-c(1,0,0,0,0,3,0,0,0,0,5,0,0,0,0,0,0,0,0,0,11,0,0,0,0)
mydata_3<-data.frame(Year_3,Value_3) 

Now the line I want is regularly plotted, but with another line following the X-axis. I did not try anything else.

Is there a way to plot mydata_2 (thus without modifying the length, as in mydata_3 ) and/or to delete the line on the X-axis in mydata_3 ?

Answer 1

Try this:

ggplot() +
  geom_bar(data = mydata, aes(fill=Name, y=Value, x=Year), position="stack", stat="identity") + 
  scale_color_viridis(discrete = TRUE)+
  scale_fill_viridis(discrete = TRUE) +
  theme(axis.line = element_blank(),
        axis.text.x=element_text(size=11,margin=margin(b=10)),
        axis.text.y=element_text(size=11,margin=margin(l=10)),
        axis.ticks.y = element_blank(),
        axis.title=element_text(size=18,face="bold"),
        panel.grid.major = element_blank(), panel.grid.minor = element_blank(),
        panel.background = element_blank(),
        legend.text = element_text(size=14,face = "italic"),
        legend.title = element_text(size=18)) +   
  geom_line(data=mydata_2, aes(x=Year_2,y=Value_2), size=1, color="red")

Answer 2

You get that error because you called aes() inside the first ggplot() , so it tries to look for Name , Value and Year .

One way to get around is to specify inherit.aes=FALSE in second geom_line :

ggplot(mydata, aes(fill=Name, y=Value, x=Year)) +
geom_bar(position="stack", stat="identity") + 
scale_color_viridis(discrete = TRUE)+
scale_fill_viridis(discrete = TRUE) +
geom_line(data=mydata_2,inherit.aes=FALSE,aes(x=Year_2,y=Value_2))

Or you call data= separately in each geom:

ggplot() +
geom_bar(data = mydata, aes(fill=Name, y=Value, x=Year),
position="stack", stat="identity") + 
scale_color_viridis(discrete = TRUE)+
scale_fill_viridis(discrete = TRUE) +
geom_line(data=mydata_2,aes(x=Year_2,y=Value_2))

Both of which gives: