R: storing plots generated in loop in list and passing to multiplot

Question

library("ggplot2")
library("Rmisc")

myplots <- list()
x = seq(1,100,1)
y = seq(1,100,1)

for(i in 1:10) {
    myplots[[i]] <- plot(x,y)
}

multiplot(plotlist = myplots, cols=2)

I receive the following error:

Error in unit(rep_len(1, nrow), "null") : 'x' and 'units' must have length > 0 In addition: Warning message: In matrix(seq(1, cols * ceiling(numPlots/cols)), ncol = cols, nrow = ceiling(numPlots/cols)) : data length exceeds size of matrix

In the real code, the for loop generates unique and meaningful plots, but I have simplified it here. — James

PKumar PKumar · Accepted Answer · 2017-12-17T06:25:34

You are not using ggplot object , you are using R base plot hence multiplot not working:

You should do this:

library("ggplot2")
library("Rmisc")

myplots <- list()
x = seq(1,100,1)
y = seq(1,100,1)
df <- data.frame(x, y)

for(i in 1:10) {
  myplots[[i]] <- ggplot(data=df, aes(x,y)) + geom_point()
}

multiplot(plotlist = myplots, cols=2)

?multiplot:

Usage

  multiplot(..., plotlist = NULL, cols = 1, layout = NULL)
Arguments

...      ggplot objects
plotlist a list of ggplot objects
cols     Number of columns in layout
layout   A matrix specifying the layout. If present, 'cols' is ignored
         Note

R: storing plots generated in loop in list and passing to multiplot

1 Answers