I input something into the R console:
> ta <- function(x,y){
+ x=x+2
+ y=y+1
+
Now my cursor is on the fourth line, I found it's x=x+1, not x=x+2.
Can I move my cursor onto the second line to revise x=x+2 into x=x+1?
As far as I'm aware, you can't do what you describe. What you can do is press Esc to cancel entering into the console and start afresh writing it in.
Are you using an IDE? Or are you writing directly into the RGui? If the latter, I heartily recommend using RStudio. It will make your life a lot easier. You'll be able to to enter text into one window and then send it into the R console when you're ready.
Alternatively. R does have an editor (File > New script) which you can use to send lines, or you can even use a txt file off to the side and only send lines when you're ready.
AFAIK, there is no way to edit the function while R is still waiting for you to close the function call. So first, I think you need to finish writing your function by typing }. Once completed, you can then do one of a few things, all of which are outlined in good detail here. I won't bother regurgitating those perfectly good answers, but do recommend you check them out. Finally, if you aren't currently using an IDE to help develop your R code, that will make your life much easier. Which IDE will be best for you is also quite subjective, but has been covered on SO here before. FWIW, I've had good luck with RStudio which is platform independent and all that good jazz...your miles may vary.
If you are running R from a terminal, you can press ctrl + c to cancel your entry and start over.
Related
I am used to starting all my Matlab scripts with clear all; close all; clc to ensure I am not looking at any old data or plots. I found Julia's clearconsole() to be equivalent to Matlab's clc, but don't have working solutions for the other two Matlab commands yet. I mostly work in the Juno IDE and run scripts with the Play ("Run All") button.
The Revise.jl package is supposed to clear the workspace now that workspace() is deprecated, but it doesn't work for this simple test case. If I define x once and then comment that line out, it will continue to print each time I run without error.
using Revise
clearconsole()
#x=1
println(x)
I know I can hit "Stop" then "Play" to reset the workspace. However, that still doesn't close old plots, and the time to first plot issue makes this option undesirable.
I found the "Forget All Plots" button in Juno's plot pane, but I would like to have that functionality as a line in my script instead. Currently, it takes me three clicks to run a script again after I edit it (four if I include "Stop").
"Forget All Plots"
Somewhere in the editor to put focus back on my current file.
"Run All"
I would ideally like to rerun in a fresh environment with one click or keystroke, but any tips on a better Juno workflow would be appreciated.
My question was answered on the Julia discourse website: link.
Juno.clearconsole() may be used like Matlab's clc.
Writing a script within a module will clear the variables upon each run like Matlab's clear all.
A new function may be added to Juno.jl in the future which will work like Matlab's close all.
I often include View() statements in my R scripts. If I accidentally forget the closing bracket at the end of the line, and then run the line of code from the script window using ctrl-enter, R just keeps trying to execute the remainder of my script. I don't know why it does that (rather than using the + symbol to prompt me to provide further input).
Moreover, I've tried to stop this by setting break points in my code - I can click on the LHS of the page and a little red circle appears. But the breakpoints don't seem to work - R just ignores them and keeps going.
The only way I can get out of it is by killing the process in the Windows task manager and then going back in afterwards. But it's wasting a lot of time.
Does anyone know how I can fix this please?
Thank you.
In effect, what your function is processing looks like that:
... %>% View(
lm(am~cyl, mtcars)
...
...
As R can't find the bracket for ) it includes remaining statements as input to View and searches for the bracket.
Solutions
Kind of depends on what you want to do with those scripts but if the intention is to run them in the background consider using callr. This package lets you run R from R and offers kill methods to kill the process you started that way.
On Windows pressing Esc should enable you to get back to the console but if it's a memory intense process it may be difficult.
You may try pressing Ctrl+c in order to kill the process.
Despite numerous searches, I can't seem to find a clear explanation as to what "Source on Save" means in RStudio.
I have tried ?source and the explanation there isn't clear, either.
As far as I can tell, it seems to run the script when I hit Save, but I don't understand the relevance/significance of it.
In simple terms, what exactly does Source on Save do and why would/should I use it?
This is kind of a shortcut to save and execute your code. You type something, save the script and it will be automatically sourced.
Very useful for short scripts but very annoying for time consuming longer scripts.
So sourcing is basically running each line of your file.
EDIT:
SO thinking of a scenario where this might be useful...
You developing a function which you will later put into a package... So you write this function already in an extra file but execute the function for testing in the command line...
Normally, you have to execute the whole function again, when you changed something. While using "Source on Save" the function will be executed and you can use Ctrl + 2 to jump into command line and test the function directly.
Since I am working with R, my datasets are much bigger. But I am remembering starting coding in python and vi, I updated my setting in a way to execute the code on save, since these little scripts where done in less then 10 seconds...
So maybe it is just not standard to work with small datasets... But I can still recommend it, for development, to use only 10% of a normal dataset. It will speed up the graphics creation and a lot of other things as well. Test it with the complete dataset every now and then.
I am writing a tool in R having a crude CLI (Command Line Interface), which does non-blocking reads from a socket (that is working). I want to concurrently check for new commands, by reading a single character (if it exists) from the console in a non-blocking manner. A simplified example
repeat{
newCmdChar <- nonblockingReadConsole()
if (newCmdChar == NULL) doStuffReadingNonblockingSocket()
else switch(newCmdChar,
a = doThis(),
b = doThat(),
x = break)
}
Various experiments failed with file("stdin") in a nonblocking manner, and permutations on scan(), readLines() etc. One approach is described here How do you read a single character from console in R (without RETURN)? but it requires working through an open graphics device and I was hoping to avoid that.
Questions
is there any way to do nonblockingReadConsole() to get a single
character? If so, how?
better to explore some R GUI package? (I'm
a newbie, ignorant to those)? If so, suggestions?
Thanks :)
/george
I'm afraid that the answer is you probably can't get input from the R GUI command line in a non-blocking way. It goes against the single-threaded nature of R.
If you need this sort of behaviour, then write the human-interaction part in a different language and call R for the calculations. Or use one of the GUI toolkits, as described in the question you linked to.
Update: I've implemented the "open grDevice with keyboard callback" approach in the link cited above, and it is working out more conveniently than expected. Cheers, /geg
UPDATE (April 2013): As per answer below, RStudio no longer jumps cursor on selection.
I'm running RStudio 0.97.168.
I like to use the script editor in RStudio like a console. Thus, I run a line of code and then edit it a little bit and re-run it. I often also explore objects by selecting some of the code and running the selection and then progressively altering the selection. At present RStudio always moves the cursor after running a line of code. The cursor can move to a variety of places. Typically the cursor moves to the next line of R code, but depending on the context, it could move to the end of the code block or the next line. It's really frustrating having to constantly move the cursor back to where I want it.
While I often appreciate the default cursor movement behaviour, I'd like to have the option to run the selection or the current line without the cursor moving.
I've raised this as a suggestion on RStudio support.
I'd like to be able to have a shortcut key like "Cmd+Alt+Enter" that runs the current line or selection and does not move the cursor in the script editor.
I realise that this is not currently supported, but I was wondering whether there might be some creative hack that could enable the cursor not to move after running a command or even a patch or perhaps some sort of external macro.
For anyone who ends up here in 2020:
Ctrl(or Cmd) + Enter: Will run current line and jump to the next one. If a code portion is selected, run the selected code without jumping further.
Alt + Enter: – Will run the current line of code without moving the cursor to the next line, useful if you want to run it multiple times.
(Source)
For this kind of flexibility, I suggest you use the editor Sublime Text 2, add in the package installer by Will Bond and then install the SublimeREPL package which will allow you to use an R interpreter within ST2 (or BASH prompt, Python / Ruby / whatever interpeter, concurrently if you wish).
You can then alternate between your code and the interpreter without lifting your fingers from the keyboard and your cursor will be at the same point every time when you want to switch back.
Sublime Text will also allow you to write a custom keybinding to automate this task.
I cannot recommend using Sublime Text 2 highly enough when coding for R. You can even pass files directly from ST2 into RStudio very easily if you like using the plot panes (very easy to do with the SidebarEnhancements package in ST2).
RStudio is awesome for many things -- especially now with Knitr, builds etc etc. But ST2 with an R REPL is many orders of magnitude more powerful for general code writing / editing than RStudio.
Sorry it's not RStudio specific, but it is a nice workaround!
I updated to version 0.98.83 of RStudio using the daily build section.
It appears that at some point in recent versions of RStudio, the cursor no longer jumps when code is run from a selection in the script window.
That's great news.