Plots not working in for loop

Question

I need to make a bunch of individual plots and want to accomplish this in a for loop. I am using ggplot2. I would just use the facet option if it could save each graph in a separate file, which I don't think it can do.

There is something going on because the plots are not saved into the files. The files are generated, though, but are empty. Here is an idea of what my code looks like:

for(i in 1:15) {    
pdf(paste("path/plot", i, ".pdf", sep=""), width=4, height=4)

abc <- ggplot(data[data[,3]==i,], 
              aes(variable, value, group=Name, color=Name)) + 
  geom_point(alpha=.6, size=3)+geom_line() + 
  theme(legend.position="none", axis.text.x = element_text(angle = -330)) + 
  geom_text(aes(label=Name),hjust=0, vjust=0, size=2.5) + 
  ggtitle("Title")

abc

dev.off()
}

How can I save the plots into these files?

Note that if I has a numeric value and I run the code inside the for loop, everything works.

Solution 1

When I use print it works:

for(i in 1:15) {   
  pdf(paste("plot", i, ".pdf", sep=""), width=4, height=4)
  abc <- ggplot(mtcars, aes(cyl, disp)) + 
    geom_point(alpha=.6, size=3)
  print(abc)
  dev.off()
}

Solution 2

Or try ggsave:

for(i in 1:15) {   
Filename <- paste("plot", i, ".pdf", sep="")
abc <- ggplot(mtcars, aes(cyl, disp)) + 
    geom_point(alpha=.6, size=3)
ggsave(filename = Filename, abc, width=4, height=4)
}

Comments

[Mehdi Nellen]

did you try print(abc)?

[saQuist]

Thanks! It worked for me without the dev.off(). With the dev.off() it seemed to clear all the plots, leading to no plots being shown in the end.