I have just started to learn to code on R, so I apologize for the very simple question. I understand it is best to type your code in as a Script so you can edit and save it. However, when I try to make an object in the script section, it does not work. If I make an object in the console, R saves the object and it appears in my environment. I am typing in a very simple code to try a quick exercise on rolling dice:
die <- 1:6
But it only works in the console and not when typed as a script. Any help/explanation appreciated!
Essentially, you interact with R environment differently when running an .R script via RScript.exe or via console with R.exe, Rterm, etc. and in GUI IDEs like RGui or RStudio. (This applies to any programming language with interactive compilers not just R).
The script does save thedie object in R environment but only during the run or lifetime of that script (i.e., from beginning to end of code lines). Your code line is simply an assignment of object. You do nothing with it. Apply some function, output results, and other actions in that script to see.
On the console, the R environment persists interactively until you quit it with q(). So assigned objects remains for lifetime of your console session. After assigning, you can afterwards apply function, output results, or other actions in line by line calls.
Ultimately, scripts gathers all line by line code in advance of run for automated execution without relying on user to supply lines. Imagine running 1,000 lines of code with nested if/then or for/while loops, apply functions on console! Therefore, have all your R coding needs summarily handled in scripts.
It is always better to have the script, as you say, you can save edit correct, without having to rewrite the code to change a variable or number.
I recommend using Rstudio, it is very practical and will help you to program more efficiently and allows you to see, among other things, the different objects that you have created.
Ok recently I have been experimenting with Julia's compose.jl and have run into a somewhat confusing problem. I will run the standard code to initialize the package.
Pkg.add("Compose")
using Compose
compose(compose(context(), rectangle()), fill("tomato"))
And then run that code. Here is my problem: the code executes fine, it's the output that is strange. The typical output for this code would be a red rectangle. The output I get when this code is run is this:
Context(BoundingBox(Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),1.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,1.0)),UnitBox{Nothing,Nothing,Nothing,Nothing}(nothing,nothing,nothing,nothing,Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0)),Rotation{Point{Measure{MeasureNil,MeasureNil},Measure{MeasureNil,MeasureNil}}}(0.0,Point{Measure{MeasureNil,MeasureNil},Measure{MeasureNil,MeasureNil}}(Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.5,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.5))),nothing,ListNode{ComposeNode}(Property{FillPrimitive}([FillPrimitive(AlphaColorValue{RGB{Float64},Float64}(RGB{Float64}(1.0,0.38823529411764707,0.2784313725490196),1.0))]),ListNode{ComposeNode}(Form{RectanglePrimitive{P<:Point{XM<:Measure{S,T},YM<:Measure{S,T}},M1<:Measure{S,T},M2<:Measure{S,T}}}(RectanglePrimitive[RectanglePrimitive{Point{Measure{MeasureNil,MeasureNil},Measure{MeasureNil,MeasureNil}},Measure{MeasureNil,MeasureNil},Measure{MeasureNil,MeasureNil}}(Point{Measure{MeasureNil,MeasureNil},Measure{MeasureNil,MeasureNil}}(Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,0.0)),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),1.0,0.0),Measure{MeasureNil,MeasureNil}(0.0,MeasureNil(),MeasureNil(),0.0,1.0))]),ListNull{ComposeNode}())),0,false,false,false,false,nothing,nothing,0.0)
a rather lengthy piece of text that doesn't show the shape... I am wondering if this is an error or if I am just doing something wrong. Does anyone know how to make this output what it should be?
One possibility to open an image through REPL would be through TerminalExtensions.jl. But generally I believe you have to write the image to a file and then open it. To save the file use this,
julia>draw(PNG("test.png", 10inch, 10inch), compose(compose(context(), rectangle()), fill("tomato")))
I'm writing all my scripts on .R file using R for mac. It is convenient to me because there are colors to highlight the type of commands.
I have a many comments following the # symbol that are useful when I forget about the meaning of my script but they tend to blur my script so that it gets harder to find a given command line.
Is there a way to hide and show these comments ? (Using the programm I'm currently using or another one). What would you suggest as the best program to write R script ?
Thanks a lot !
RStudio supports code folding. You can standardize your comment blocks so that they are recognized as code blocks.
For example, enter this into your RStudio editor
#=======================================================
# this is a comment block
# more comments here
# comments upon comments
and then press Alt+L to fold, and Alt+Shift+L to unfold.
Try RStudio for mac. One of the greatest code writing environment for R there is.
You can also try Emacs, which is more like old-fashioned command line editor. You can find a good guide here.
I am running a set of selected code on R. Like
source("/tmp/r-plugin-honli/Rsource-2704-quantmod.R")
There is no output. Only the prompt '>' flickered there.
I use 'killall' to kill the R session. But I don't know where is wrong on the code. Because R did not give any output. How could I know what's going on about the code.
I'd try two things:
Run the code interactively. As in, open the Rsource-2704 file and run its lines one by one.
If that doesn't replicate the problem or is not possible, you can take Joshua Ulrich's suggestion or use:
R CMD BATCH --vanilla Rsource-2704-quantmod.R out.log
Which will run the code in a batch mode and output the usual console lines to a file called out.log (you can name it whatever you like).
Instead of using print statements, you could also take a look at the browser() command. This drops you into an interactive session at the point where the command is put. This works particularly well when trying to figure out what is happening inside a function, although I don't know if your script contains them.
I've an R script, that takes commandline arguments, where the top line is:
#!/usr/bin/Rscript --slave
I wanted to interrupt execution in a function (so I can interactively use the data variables that have been loaded by that point to work out the next bit of code I need to write). I added this inside the function in question:
browser()
but it gets ignored. A bit of searching suggests it might be because the program is running in non-interactive mode. But even more searching has not tracked down how I switch the script out non-interactive mode so that browser() will work. Something like a browser_yes_I_really_mean_it() function.
P.S. I want to avoid altering the rest of the script if at all possible. My current approach is to copy and paste the code chunks, needed to prepare the data, into an interactive session; but as the script gets more and more complex this is getting more and more unreasonable.
UPDATE: for anyone else with the same question, it appears the answer to the actual question is that it is impossible. Once you start R in a non-interactive mode the die is cast. The given answers are therefore workarounds: either you hack your code (remembering to unhack it afterwards), or you refactor to make debugging easier. (This comment is not intended as a criticism of the answers; the suggested refactoring makes the code cleaner anyway.)
Can you just fire up R and source the file instead?
R
source("script.R")
Following mdsumner's answer, I edited my script like this:
if(!exists("argv")){
argv=commandArgs(TRUE)
if(length(argv)!=4)usage_and_exit()
}else{
if(length(argv)!=4){
stop("Must set argv as a 4 element vector. E.g. argv=c(...)")
}
}
Then no other change was needed, and I was able to do:
R
> argv=c('a','b','c','d')
> source("script.R")
In addition to the previous answer, I'd create a toplevel function (e.g. doStuff) which performs the analysis you want to perform in batch. The function takes the cmd line options as input. In the batch script you source the script that contains this function and call it. In this way you can easily run the function in interactive mode and use e.g. browser().
In some cases, the suggested solution (workaround) may not work - for example, when the R code needs to be run as a part of an existing bash script. For those cases, I suggest to write in your R script into the bash script using here document:
#!/bin/bash
R --interactive << EOT
# R code starts here
argv=c('a','b','c','d')
print(interactive())
# Rest of script contents
quit("no")
# R code ends here
EOT
This way, print(interactive()) above will yield TRUE.
Sidenote: Make sure to avoid the $ character in your R code, as this would not be processed correctly - for example, retrieve a column from a data.frame() by using df[["X1"]] instead of df$X1.