remove all variables except functions

Question

I have loaded in a R console different type of objects. I can remove them all using

rm(list=ls())

or remove only the functions (but not the variables) using

rm(list=lsf.str())

My question is: is there a way to remove all variables except the functions

Solution 1

Here's a one-liner that removes all objects except for functions:

rm(list = setdiff(ls(), lsf.str()))

It uses setdiff to find the subset of objects in the global environment (as returned by ls()) that don't have mode function (as returned by lsf.str())

Solution 2

The posted setdiff answer is nice. I just thought I'd post this related function I wrote a while back. Its usefulness is up to the reader :-).

lstype<-function(type='closure'){ 
    inlist<-ls(.GlobalEnv)
    if (type=='function') type <-'closure'
    typelist<-sapply(sapply(inlist,get),typeof)
    return(names(typelist[typelist==type]))
}

Solution 3

You can use the following command to clear out ALL variables. Be careful because it you cannot get your variables back.

rm(list=ls(all=TRUE))

Comments

[Josh O'Brien]

If you also want to remove objects whose names start with a period, use this instead: rm(list=setdiff(ls(all.names=TRUE), lsf.str(all.names=TRUE)))

[Josh O'Brien]

Thanks for posting that. It makes for an interesting comparison with the code for ls.str() which, however, tests the mode rather than the typeof of objects. (On a side note, I'll be darned if I can figure the difference between those two from their documentation).

[RockScience]

Thanks a lot for this answer. May I know what is a period?

[RockScience]

I always use class instead of typeof

[Josh O'Brien]

Sure. A period (in American English) is another name for a dot, like this: . To see what I'm talking about, try .j <- 5; ls(); ls(all.names=TRUE)

[RockScience]

great, thank you. I already noticed that .j was not affected by ls() but could explain that.

[RockScience]

Good to know but that's not the not the question

[lwileczek]

I guess I should have left that as a comment since it was more of an FYI. Sorry.

[DiveIntoML]

Please add more information about "current environment", e.g. whether this is shell or certain programming language