2012年6月13日 · My apologies as this is not a reproducible code kind of question, but I'm not sure how to approach making R ask questions as opposed to me asking question about R!

There may be situations in which you do not exactly know the name of the variable you are looking for, like when an array of results have been created by a queuing system. These can possibly be addressed with "ls" and its argument "pattern" that expects a regular expression. The "exists" function could be reimplemented that way as exists <-function(variablename) { #print(ls(env=globalenv ...

2015年2月12日 · @Marek is very right. A few more remarks : In general, you shouldn't be using scan() but readline() for this. I'd split the code so it becomes clear what serves to read in n, and what serves to read in acr. think about whether you want to return to the prompt when people just press enter, or whether you want to reask the question until they fill in some correct value. you can use the power of ...

2014年1月31日 · If you read ?update.pacakges, then you'll notice that the first argument to update.packages is not the package name, but the library location to check. If you only want to update one package, use install.packages. The warning you report tells you why it doesn't work: you have to stop using the package in all the R sessions that are using it. This is most easily accomplished by closing the ...

2017年9月8日 · I would like to read an input given by User in R programming through message window. For example, It should give a message "enter the number" in a pop up box along with option of entering a number...

Subsetting is quite important to learn if you really want to use R efficiently, so perhaps you want to take a look at An Introduction to R to get started.

2013年3月8日 · What is the possible documentation available for R package? For example I try to understand sp package. In addition to help(sp), what are the other functions for searching through help and

Using exists() on a list does work, but I believe that R internally coerces it to an environment before checking for an object of that name, which is inefficient and can result in errors if there are any unnamed elements.

Please try a simple google search before posting! Typing "r get current working directory" gets me the man page answering your first two questions as its first hit.

2016年8月22日 · In non-interactive use the result is as if the response was RETURN and the value is "". You have stumbled on one of the "surprising" features of R. <rant> Why readline() works in "interactive mode" only is a complete mystery for me, since it's a perfectly acceptable use case to ask for user input from within a script.