Error in dev.off() : cannot shut down device 1 (the null device)
When you receive the error message “Error in dev.off() : cannot shut down device 1 (the null device)” in R or RStudio, it typically means that there was an issue with opening or closing a graphics device.
In R, the dev.off() function is used to close the current graphics device and switch back to the default device. It is commonly used after generating plots or visualizations.
This error occurs when the device that R is trying to close is the null device, which is essentially a non-existent or not properly initialized device. The null device (device 1) is used when R is not outputting graphics to any physical devices or screens. It is often encountered when generating plots within certain environments or when a previous plot did not close properly.
To better understand this error, let’s consider a couple of examples:
Example 1:
# Open a graphics device
pdf("plot.pdf")
# Generate a plot
plot(1:10)
# Close the graphics device
dev.off()
In this example, we open a PDF device using the pdf() function and generate a simple plot. The plot is then saved to a file using dev.off(). If you encounter the mentioned error after running this code, it could be due to a problem with the PDF device initialization or the plot not being closed properly in a previous session. To resolve this, you can try restarting the R session or running graphics.off() to shut down all active graphics devices before creating a new one.
Example 2:
# Generate a plot but don't close the previous device
plot(1:10)
# Open a new graphics device
png("plot.png")
# Generate another plot
plot(11:20)
# Close the graphics device
dev.off()
In this example, a plot is generated without closing the previous graphics device. Then, a PNG device is opened using png() and another plot is created. Finally, the device is closed using dev.off(). If you encounter the mentioned error after running this code, it indicates that the previous device (null device) was not closed properly before opening the PNG device. To fix this, you can close the previous device using dev.off() or graphics.off() before opening the new device.