**How do I clear screen in julia-app mac OS-X **
In mac terminal - clear would clear the terminal screen.
How do I do the same in julia interactive app in Mac OS X?
Use keyboard shortcut: Ctrl + L.
Use Julia's REPL shell mode:
julia> ; # upon typing ;, the prompt changes (in place) to: shell>
shell> clear # unix
shell> cmd /c cls # windows
If you need a function you could use the run function:
julia> ? # upon typing ?, the prompt changes (in place) to: help>
help?> run
INFO: Loading help data...
Base.run(command)
Run a command object, constructed with backticks. Throws an error
if anything goes wrong, including the process exiting with a non-
zero status.
julia> using Compat: #static, is_unix # `Pkg.add("Compat")` if not installed.
julia> clear() = run(#static is_unix() ? `clear` : `cmd /c cls`)
clear (generic function with 1 method)
julia> clear()
This works in a platform and version independent way (tested in Windows and Linux, Julia versions 0.3.12, 0.4.5 and 0.5.+).
Try Ctrl+L if you want to clear the screen the interactive shell runs in. Same as bash.
A partial answer
Create a function clear() to print new line characters
clear() = for i in 1:20
print("\n")
end
Then invoke the function
clear()
Related
Anyone got an idea why
system2("bash", "ls")
would result in (both in R-Gui and RStudio Console)
/usr/bin/ls: /usr/bin/ls: cannot execute binary file
while other shells work w/o issues (see example below) and the "bash" in the RStudio Terminal also works w/o problems. AND if there is a remedy for that?
Working system2 example:
system2("powershell", "dir")
Running R-3.6.3 on Windows 10 here ... with "Git bash" executing as "bash".
PS: just in case someone wonders - I also tried the full path ie /usr/bin/ls -> same result
Ok - this does the trick
system2("bash", input = "ls")
so instead of args = ... as with the powershell command one needs (or more interestingly sometimes 'can') use the input = ... parameter with bash
OR as mentioned in the comments by #oguzismail this will also work
system2("bash", "-c ls")
as well as pointed out by #Christoph
system2("ls")
also works sometimes (ie in some RStudio[?] setups it will not return results in some it will).
But I have come to notice that different combinations of R-versions with different RStudio versions [or more probably Locales] will not always behave consistently of course also depending on the availability of bash commands like ls (more generally /usr/bin) being on the PATH or not.
So choose what suits u best!
I am trying to pause my code for a little while, time for me to observe the plots.
I tried:
print('A')
something = readline("Press Enter")
print('B')
print('C')
, then there is no pause, the line print('B') is fed to readline and get stored into something and therefore only A and C got printed on the screen. Note that if I add an empty line between Something = readline("Press Enter") and print("B"), then print("B") get printed on the screen but still the console doesn't allow the user to press enter before continuing.
And I tried:
print('A')
Sys.sleep(3)
print('B')
print('C')
The program waits 3 seconds before starting and then run "normally" without doing any pause between print('A') and print('B').
What do I missunderstand?
Here is my R version: R 3.1.1 GUI 1.65 Snow Leopard build (6784)
The problem with readline is that if you paste your script into an R console, or execute it from eg Rstudio, the redline function is read and then the next line of the script is read in as the console entry, which in your case sets the value of something to print('B).
An easy way to get around this is to stick your entire code in a function, then call the function to run it. So, in your case:
myscript = function(){
print('A')
something = readline(prompt = "Press Enter")
print('B')
print('C')
}
myscript()
The output of this for me (in Rstudio, with R version 3.1.1):
[1] "A"
Press Enter
[1] "B"
[1] "C"
This has always felt like a bit of a hack to me, but it's essentially what the readline documentation recommends in its example.
I've never used sleep in my code, so I can't help you there.
Edit to clarify based on comments: This will only work if myscript() is the very last line of your script, or if it is manually entered into the console after running the script to generate the function. Otherwise, you will run into the same problem as before- the next line of code will be automatically entered.
I am trying to run the following command from Julia:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/user/.julia/v0.3/Smile/deps/downloads
When I run it as-is it tries to replace $LD_LIBRARY_PATH with a local variable.
When I escape the $, it puts quotes around the command, which invalidates it.
julia> cmd = `export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/tim/.julia/v0.3/Smile/deps/downloads`
ERROR: LD_LIBRARY_PATH not defined
julia> cmd = `export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:/home/tim/.julia/v0.3/Smile/deps/downloads`
`export 'LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/tim/.julia/v0.3/Smile/deps/downloads'`
I would like to run the command in a form similar to:
run(`export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$newpath`)
How do I properly handle the dollar sign?
Thank you
*note: pasting the command directly into terminal and running it does work
In Julia, backticks are not completely equivalent to running the corresponding command at the shell. You can't interpolate environmental variables with $ (although $(get(ENV, "varname", "") should match the shell's behavior), and export is a shell built-in, not a command, so I don't think you can run it. Also, even if backticks shelled out, export would only change the environment of the subshell, not the calling process.
You should be able to set LD_LIBRARY_PATH from Julia as:
ENV["LD_LIBRARY_PATH"] = "$(get(ENV, "LD_LIBRARY_PATH", "")):$newpath"
but you should avoid this if possible. If your intent is to ccall a specific library, you can pass the library path directly to ccall, perhaps using find_library as you indicated in a comment if you don't know the full path advance. If you need to set LD_LIBRARY_PATH because the library needs to load other libraries, I'm not sure if there's a better way, but note that LD_LIBRARY_PATH is platform-specific. You might be able to dlopen the dependent libraries first, but I haven't tested that.
I am enjoying developing inside the ipython notebook, but I am having a problem when I want to write a main() function that reads the command line args (with OptionParser, for example). I want to be able to export the code to a .py file and run it from the command line, but I haven't found a way to have a main() that runs both in the notebook with predefined arguments or from the command line with python and command line args. What is the secret?
In case that is not clear, I would like to do something like this:
if __name__ == '__main__':
# if in the notebook
vals = {'debug':True, 'tag_file': 't.tags'}
options = Object()
for k,v in vals.items():
options.setattr(k,v)
args = 'fname1.txt'
# if running as a command line python script
from optparse import OptionParser
parser = OptionParser()
parser.add_option('-d','--debug',action='store_true',dest='debug')
parser.add_option('-t','--tags',action='store',dest='tag_file')
options,args = parser.parse_args()
You cannot determine that you are in an IPython notebook or a qtconsole, or a simple IPython shell, for the simple reason the 3 can be connected to the same kernel at the same time.
It would be like asking, what color is the current key the user is typing. You could get it by looking the plugged usb devices and look for images on the internet and guess the keyboard color, but nothing guarantees you it will be accurate, nor that it won't change, and user can have multiple keyboard plugged, or even painted keyboard.
It is really the same with the notebook, Even if you determine you are in ZMQKernel, are you speeking to qtconsole or webserver ? Again, you found that you were talking to the webserver, are you talking to JS or Emacs ? And so on and so forth.
The only thing you can do, you can ask the user.
What is reliable, is test wether you are in IPython or not.
If you really but reeaaalllyy want a way, as until now, the notebook is the only thing that can display Javascript. And javascript can execute code in pyton. So you might be able to create something that display JS that send back info to the kernel. And using thread and timer you can say that you were not in a notebook (but you will have a race condition).
Don't worry about the distinction. Just set default values, and unless they are overridden from the command line, use those.
if __name__ == '__main__':
parser = OptionParser()
parser.add_option('-d', '--debug', action='store_true', dest='debug',
default=True)
parser.add_option('-t','--tags',action='store',dest='tag_file',
default='t.tags')
options, args = parser.parse_args()
if not args:
args = ['fname1.txt']
I am trying to call a Windows program called AMDIS from within R using the call
system("C:/NIST08/AMDIS32/AMDIS_32.exe /S C:/Users/Ento/Documents/GCMS/test_cataglyphis_iberica/queens/CI23_Q_120828_01.CDF")
in order to carry out an analysis (specified using the /S switch) on a file called CI23_Q_120828_01.CDF, but it seems that no matter what I try the file is not loaded in correctly, presumably because the options are not passed along. Does anyone have a clue what I might be doing wrong?
Right now this command either
doesn't do anything,
makes AMDIS pop up, but it doesn't load the file I specify
gives me the error
Warning message:
running command 'C:/NIST08/AMDIS32/AMDIS_32.exe /S
C:/Users/Ento/Documents/GCMS/test_cataglyphis_iberica/queens/CI23_Q_120828_01.CDF'
had status 65535
(I have no idea what results in these different outcomes of the same command)
(the AMDIS command line options are described here at the page 8)
Cheers,
Tom
EDIT:
Found it had to do with forward vs backslashes - running
system("C:\\NIST08\\AMDIS32\\AMDIS_32.EXE C:\\Users\\Ento\\Documents\\GCMS\\test_cataglyphis_iberica\\queens\\CI23_Q_120828_01.CDF /S /E")
seems to work - thank you all for the suggestions!
You've heard of bquote , noquote , sQuote, dQuote , quote enquote and Quotes, well now meet shQuote!!! :-)
This little function call works to format a string to be passed to an operating system shell. Personally I find that I can get embroiled in backslash escaping hell, and shQuote saves me. Simply type the character string as you would on the command line of your choice ('sh' for Unix alikes like bash , csh for the C-shell and 'cmd' for the Windows shell ) wihtin shQuote and it will format it for a call from R using system:
shQuote("C:/NIST08/AMDIS32/AMDIS_32.exe /S C:/Users/Ento/Documents/GCMS/test_cataglyphis_iberica/queens/CI23_Q_120828_01.CDF" , type = "cmd" )
#[1] "\"C:/NIST08/AMDIS32/AMDIS_32.exe /S C:/Users/Ento/Documents/GCMS/test_cataglyphis_iberica/queens/CI23_Q_120828_01.CDF\""
More generally, you can use shQuote like this:
system( shQuote( "mystring" , type = c("cmd","sh") ) , ... )