R Programming on plot to label the axes - r

Create a plot with cars dataset and attribute speed along the X axis and distance in y axis .
Label the axes.
I have done this programming still there is some problem:
plot(cars,xlab="speed",ylab="distance")
Even though everything seems correct the terminal doesn't move to the next part

What environment are you using? I was able to execute the following code and produce the plot you want using both RStudio and R directly in the terminal.
library(MASS)
plot(cars, xlab="Distance", ylab="Speed")
If you're running straight from the terminal then you'll need to specify a window to pop up. The following question has an answer that outlines what to do depending on your operating system:
How to pop up the graphics window from Rscript?
So, for example, if you don't have your system configured to automatically open the plot window, and you're running on a mac, the following code will produce what you want directly from running R in the terminal:
library(MASS)
X11()
plot(cars, xlab="Distance", ylab="Speed")

Related

Creating plot using R under Mac OS

I use R in Mac through command line. When I need to draw some plot, R open plotting device called Quartz to display plot. It all works fine, but problem arise when I update a plot or draw a new plot based on changed plot. It looks like Quartz device does not automatically update the same. I need to close Quartz before I update my data and hit enter, so that new/modified plot can appear in Quartz.
I am wondering if this is default behaviour when R is run from command line in Mac? Is there any way to automatically update the plot in Quartz every time I update the data for plotting?
Any pointer will be highly appreciated.

Saving filled contour plots to PDF in R gives pixelated results

Saving the output of one of R's built-in examples for the filled.contour function to PDF:
pdf('test.pdf')
require("grDevices")
filled.contour(volcano, asp = 1)
dev.off()
produces a discretised result (see below). Is there any way to fix this? System info:
> sessionInfo()
R version 3.6.3 (2020-02-29)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.1 LTS
Edit after the accepted answer:
The problem is actually reported in the documentation of the pdf function:
If you see problems with PDF output, do remember that the
problem is much more likely to be in your viewer than in R ...
Symptoms for which the viewer has been at fault are apparent
grids on image plots ...
Unfortunately the default viewers on most Linux and macOS
systems have these problems, and no obvious way to turn off
graphics anti-aliasing.
It's an odd place to document the problem because the subdivision into rectangular segments is clearly caused by filled.contour and not by pdf. Otherwise ggplot2's output would also suffer from the same issue.
That is likely a result of antialiasing: when you display the image, it draws squares one at a time. As they are being drawn, the edge is a mix of the square colours and the white background, so it is drawn lighter.
Unfortunately, this isn't something that's really under your control. It's the PDF previewer that is introducing the artifacts. See this page https://codedocean.wordpress.com/2014/02/03/anti-aliasing-and-image-plots/ for a discussion.
The recommendation there worked for me: use the png() device with type = "cairo". This gives bitmapped output rather than the vector output of a pdf().
png('test.png',type="cairo")
filled.contour(volcano, asp = 1)
dev.off()
Edited to add:
I don't think you can do better with filled.contour, but if you are willing to switch to ggplot2 graphics you can. When it draws filled contours it appears to do it using polygons, not the image style plot that filled.contour uses. This still shows the same antialiasing bugs in the previewer, but now the lines appear along the borders between colours, which is much less irritating. For example:
df <- data.frame(x = as.numeric(row(volcano)-1)/(nrow(volcano)-1),
y = as.numeric(col(volcano)-1)/(ncol(volcano)-1),
z = as.numeric(volcano))
pdf('test.pdf')
library(ggplot2)
ggplot(df, aes(x=x, y=y, z=z)) +
geom_contour_filled()
dev.off()
I don't know how to get the same palette as filled.contour uses, i.e. function(n) hcl.colors(n, "YlOrRd", rev = TRUE). Maybe someone else can show us in a comment.

How do you delete the current (but not all) plots in the RStudio plotting device?

How do you delete the current (but not all) plots in the RStudio plotting device?
dev.off() will remove all plots, but what if I just want to remove one? I don't want to have to press that red 'x' button because I want to remove one plot without pressing a button.
In R, you would just use dev.new() before each plot, so you dev.off() to only clear the last plot.
In RStudio, you can use x11(), windows() or quartz() (depending on your device) before each plot. Then call dev.off() to clear last plot. You can also use dev.set() to choose specific plots that way.
If your question is specifically asking to delete the last plot within the same RStudio window (rather than making new windows), not sure if it's possible, since RStudio treats that window as one device. An idea would be to look at a way to call the C++ function removePlot() in the RStudio project.
I found in the Github repository for RStudio the C++ code:
display.removePlot(display.activePlotIndex());
You could output the plots and manage the files that way.

How to keep previous plots and windows in Gnuplot?

I have some problems of using gnuplot. I just begin with it.
(1)What is the command for keeping the previous plot when I plot new data? Do I have to plot the old data and the new data at the same time?
(2)What is the command for open a new window while keep the old ones? Do I have to set the window's id by using, e.g.,
set terminal wxt 3
, before each plot?
Can anyone give me some help or some good references?
Usually, to plot several data set you would use
plot 'data1.dat', 'data2.dat'
You could also use replot to add one of the data sets later
plot 'data1.dat'
...
replot 'data2.dat'
To open a new window, you must use the window's id like with set terminal wxt 2. The old windows stay open, but you cannot interact with them anymore (zooming, scrolling etc.). See also the discussion to the quesiton Two interactive windows in Gnuplot with wxt terminal.
You already wrote the answers of your questions.
1.: You can use the replot command:
plot sin(x)
replot cos(x)
but this just expands to
plot sin(x), cos(x)
So, it replots all data and does not just add the cos(x).
2.: Yes, you can also switch between the windows to update the plots. But note that settings like ranges and labels are not stored per window / plot, but globally. If they are different for different plots, you have to change them every time.
You may also have a look at "set multiplot" to put several plots on one window / picture. But it is not so nice for interactive plotting, as you will notice.
Also, output terminals supporting multiple pages like pdfcairo will add a new page for each plot.

Repeat plot command with minor changes in R

I made a plot in R and I want to repeat all the commands (like plot(), legend() or line()) that were carried out for this plot, with some minor changes. For example I want to set the axes to logarithmic scale and change the title of the plot.
In gnuplot I would use the replot command.
plot ...
set title "The same plot with logarithmic axes"
set logscale
replot
Is something like this possible in R. The only thing that comes to my mind of doing this (besides changing the values manually and re-run the lines of codes) would be setting up a function, that asks for all parameters that might be changed by the user.
Thanks for your help,
Sven
R uses a pen and paper graphics model - once the plot has been drawn on the device that is it. If you want to change some aspect of the plot, you need to replay the graphics function calls that produce the plot with the changes made to the code.
Depending on what you are really doing there are two options:
If this is just for you, write code in a text editor / IDE that knows R and can send chunks of code at a time to R. That way the code to produce the figure is recorded in a separate script which you can paste into/send to R making the changes you need each time to the script.
If you are going to be doing this often, then write yourself a wrapper plotting function that encapsulates the plot code you want but allows you to pass in arguments to alter the aspects you want.
Lattice and ggplot2 are a little different as they are based on grid graphics and create objects that when printed produce a plot on the device. One can manipulate that object to alter what is drawn, and with grid one can push and pop things on to / off a viewport.

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