How to loop a ggplot graph in r

Question

I have a data set (A2) which looks like this;

Year    Gear      Region    Landings.t
1975    Creel     Clyde     3.456
1976    Creel     Clyde     20.531
1977    Creel     Clyde     56.241
1978    Creel     Clyde     43.761
1975    Creel     Shetland  3.456
1976    Creel     Shetland  10.531
1977    Creel     Shetland  46.241
1978    Creel     Shetland  33.761

and I am using the following code to generate a line graph;

ggplot(subset(A2,Region=="Clyde"),aes(x=Year,y=Landings.t,colour=Gear,group=Gear))+
  geom_line()+
  facet_grid(Gear~.,scales='free_y')+
  ggtitle("CLYDE LANDINGS BY GEAR TIME-SERIES")+
  theme(panel.background=element_rect(fill='white',colour='black'))+
  geom_vline(xintercept=1984)

at the moment I am replicating the code for each different region which is making my script very long. I was wondering if there is a way to loop the code to go through each of the regions and generate a plot for each?

I have tried using the answers available from this previous question Loop through a series of qplots but when I use this code it returns a 'non-numeric argument to binary operator' error.

for(Var in names(A2$Region)){
print(ggplot(A2,[,Var],aes(x=Year,y=Landings.t,colour=Gear,group=Gear))+
geom_line()+
facet_grid(Gear~.,scales='free_y')+
ggtitle("CLYDE LANDINGS BY GEAR TIME-SERIES")+
theme(panel.background=element_rect(fill='white',colour='black'))+
geom_vline(xintercept=1984)
}

names(A2$Region) will return NULL. You probably want unique there. There is also a , after A2 where I think you want to subset. — LyzandeR
– LyzandeR, Commented Oct 2, 2015 at 11:10

bbiasi · Accepted Answer · 2020-11-01 11:08:31Z

2

for(Var in unique(A2$Region)){
  print(
    ggplot(
      subset(A2, Region == Var),
      aes(x = Year, y = Landings.t, colour = Gear, group = Gear)
    )+
    geom_line() +
    facet_grid(Gear ~ ., scales = 'free_y') +
    ggtitle("CLYDE LANDINGS BY GEAR TIME-SERIES") +
    theme(panel.background = element_rect(fill = 'white', colour = 'black'))+
    geom_vline(xintercept = 1984)
  )
}

or using the plyr package

library(plyr)
dlply(A2, ~Region, function(x){
    ggplot(
      x,
      aes(x = Year, y = Landings.t, colour = Gear, group = Gear)
    )+
    geom_line() +
    facet_grid(Gear ~ ., scales = 'free_y') +
    ggtitle("CLYDE LANDINGS BY GEAR TIME-SERIES") +
    theme(panel.background = element_rect(fill = 'white', colour = 'black'))+
    geom_vline(xintercept = 1984)
})

plyr makes it easy to split the dataset along multiple variables.

dlply(A2, ~Region + Species, function(x){
    ggplot(
      x,
      aes(x = Year, y = Landings.t, colour = Gear, group = Gear)
    )+
    geom_line() +
    facet_grid(Gear ~ ., scales = 'free_y') +
    ggtitle("CLYDE LANDINGS BY GEAR TIME-SERIES") +
    theme(panel.background = element_rect(fill = 'white', colour = 'black'))+
    geom_vline(xintercept = 1984)
})

edited Nov 1, 2020 at 11:08

bbiasi

1,6092 gold badges19 silver badges32 bronze badges

answered Oct 2, 2015 at 11:19

Thierry

18.5k5 gold badges51 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

helen.h Over a year ago

Is there a way of putting that loop within another loop. I want to have the same plots for each species but still by each region. Can you have two back to back 'for' satements?

helen.h Over a year ago

I am struggling with generating appropriate titles for each looped plot; with the first answer you gave me I have been using 'ggtitle(paste(Var,"landings by gear time-series")) which worked fine however I can't get a similar line to work for the plyr multiple variables code. I have tried a number of different arrangements but I am getting the Error: object 'Species.Code' not found or it is just giving them all the same region and species name.

Thierry Over a year ago

use something like ggtitle(paste("fixed title", x$Species[1]))

Collectives™ on Stack Overflow

How to loop a ggplot graph in r

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related