Remove all objects of a given type in R

Question

How can I use rm to remove all objects of a certain type in R?

I currently have a bunch of functions defined that I'd like to expunge.

I know ls has a pattern option, but this would only help if I was naming all the functions in a pattern (I'm not).

Answer 1

A variation on @Jilber's answer:

rm(list=names(Filter(is.function, mget(ls(all=T)))))

Answer 2

You may try ls.str where you can list objects of a certain mode (e.g. integer, list (data frame) or function), or lsf.str (returns functions only):

# some objects to 'look for'
int1 <- 1
char1 <- "a"
list1 <- data.frame(x1, x2)
fun1 <- function() x1 + x2

# ls()
# ls.str()
ls.str(mode = "function")
funs <- as.character(ls.str(mode = "function"))

lsf.str()
funs <- as.character(lsf.str())

# rm(funs)

Answer 3

My solution is basically to use mget to get the class of everything in ls(), then subset ls() according to when class=="function":

rm(list=ls(all=TRUE)[sapply(mget(ls(all=TRUE)), class) == "function"])

@Jilber suggests a cleaner alternative:

rm(list=ls(all=TRUE)[sapply(mget(ls(all=TRUE)), is.function)])

These basic approaches can be expanded to accommodate more complex "genocide" (class-specific purging):

rm(list=ls(all=TRUE)[sapply(mget(ls(all=TRUE)), class) %in% 
    c("function", "numeric")])
rm(list=ls(all=TRUE)[sapply(mget(ls(all=TRUE)),
                            function(x) is.function(x) | is.numeric(x))])

@Jilber's approach also has the advantage that it will catch multi-class objects (most notably, data.tables.

Suppose we wanted to remove all data.frames that are not (also) data.tables:

rm(list=ls(all=TRUE)[sapply(mget(ls(all=TRUE)),
                            function(x) is.data.frame(x) & !is.data.table(x))])

Answer 4

There is an ls.str() function that accepts a mode argument. You can get all the functions in the global environment with:

ls.str( mode="function")  # or in a different environment if properly created

The exists function tests whether it can be found and can be limited to particular mode. This is a potentially destructive effect on a running session

rm( list = ls()[ sapply( ls(), exists, mode="function")] )
# test for errors and effectiveness
any( sapply( ls(), exists, mode="function"))
# [1] FALSE

If you were trying to remove only functions with particular patterns to their names you might select among the character vectors returned by ls() with grepl.