environment

This question already has an answer here: How to check if object (variable) is defined in R? 6 answers I want to determine whether an object exists inside a function in R: foo <- function() { y <- "hello" if (exists(y, envir = sys.frame())) print(y) } foo() Error in exists(y, envir = sys.frame()) : invalid first argument I thought adding the envir = sys.frame() would do the trick. Also tried envir = environment() Expected foo() "hello" You should have checked ?exists : Usage: exists(x, where = -1, envir = , frame, mode = "any", inherits = TRUE) Arguments: x: a variable name (given as a

I've decided to get rid of rvm, and I'm having trouble compiling a gem with my new version of ruby 1.9.2. The gem requires 1.9.2, I have it, yet says it can't install without, so the error messages makes no sense. How can I explicitly tell the gem to compile with said version of ruby? Gem::InstallError: linecache19 requires Ruby version >= 1.9.2. An error occured while installing linecache19 (0.5.12), and Bundler cannot continue. Make sure that `gem install linecache19 -v '0.5.12'` succeeds before bundling. apps2 ~/projects/sms/apps2/apps2_admin $ ruby -v ruby 1.9.2p180 (2011-02-18 revision

How can I get to know what my desktop environment is using Python? I like the result to be gnome or KDE or else. Tested in Ubuntu 9.10: >>> import os >>> os.environ.get('DESKTOP_SESSION') 'gnome' Edit: As mentioned in comments below, this approach will not work for more some OSes. The other two answers provide workarounds. I use this in one of my projects: def get_desktop_environment(self): #From http://stackoverflow.com/questions/2035657/what-is-my-current-desktop-environment # and http://ubuntuforums.org/showthread.php?t=652320 # and http://ubuntuforums.org/showthread.php?t=652320 # and http

This question comes from a range of other questions that all deal with essentially the same problem. For some strange reason, using a function within another function sometimes fails in the sense that variables defined within the local environment of the first function are not found back in the second function. The classical pattern in pseudo-code : ff <- function(x){ y <- some_value some_function(y) } ff(x) Error in eval(expr, envir, enclos) : object 'y' not found First I thought it had something to do with S4 methods and the scoping in there, but it also happens with other functions. I've