Plotting a graph in R and exporting it to Excel in a loop

Question

In my data I have multiple countries and each country has 5 products. I performed a regression for each combination and now I am trying to plot the predicted values vs. the actual values on the same graph, for each combination.

I have 10 countries in total and each country has its own tab in an Excel file. Since there are 5 products, this is a total of 50 graphs. I want to plot the graphs in R and export them to Excel in a loop. I am using excel.link package ggplot and the issue that I'm having is that the graphs appear as blank space in Excel or if there was some graph in R - that graph appears instead of the required graph.

**Note: I used to get an error with the first graph that said "rversion not found" but now I updated my RStudio and I no longer get this error. The graph still gets exported blank or the previous graph appears instead

Here is a simplified loop, similar to the one that is in my code. If I run the loop manually, by changing i each time, everything gets exported OK. If I run the for loop, the issues happen that I described above:

require(excel.link)

set.seed(124)

for(i in 1:5){

# i <- 2
myseq <- seq(1,100, by=1)
norm <- rnorm(100)

mydata <- as.data.frame(cbind(myseq, norm))
colnames(mydata)
ggplot(data = mydata, aes(x=myseq, y=norm, group=1)) + geom_line(size=1, col="blue") +
  ggtitle(paste("My Plot ", i))

y.plot=current.graphics()
xl[a1] = list(y.plot)

}

Answer 1

First of all you should print explicitly ggplot2 graphics in the loop. Second, you put plots in excel in the same sheet in the same position. So your graphs are placed one on each other and you will see only last plot in Excel. Code for displaying plots on separate sheets:

library(excel.link)
library(ggplot2)

set.seed(124)
xl.workbook.add() # open new workbook
for(i in 1:5){

    myseq <- seq(1,100, by=1)
    norm <- rnorm(100)

    mydata <- as.data.frame(cbind(myseq, norm))
    colnames(mydata)
    p = ggplot(data = mydata, aes(x=myseq, y=norm, group=1)) +
        geom_line(size=1, col="blue") +
        ggtitle(paste("My Plot ", i))

    print(p) ## display ggplot graphics
    y.plot=current.graphics()
    xl.sheet.add() ## add new sheet in excel workbook
    xl[a1] = y.plot

}

Code for displaying plots on the single sheet from top to down:

library(excel.link)
library(ggplot2)

set.seed(124)
xl.workbook.add() # open new workbook
y.plot = lapply(1:5, function(i) {

    myseq <- seq(1,100, by=1)
    norm <- rnorm(100)

    mydata <- as.data.frame(cbind(myseq, norm))
    colnames(mydata)
    p = ggplot(data = mydata, aes(x=myseq, y=norm, group=1)) + 
        geom_line(size=1, col="blue") +
        ggtitle(paste("My Plot ", i))

    print(p) ## display ggplot graphics
    current.graphics()

})

xl[a1] = y.plot