R help - May 2014 - Is there an easier way than this to list all functions in the global environment?

After an unsuccessful search thru several books plus online documentation, I was
unable to find a simple way to do this, so I wrote my own function (see below)
to do it. ?I'm relatively new to R however, so I'm guessing that there
must be an easier way to do it.

I want to list all functions and only the functions (not other objects also) in
the global environment.

I'm working with several old R workspaces that contain a very large number
of objects -- functions, data structures, etc. and I would to be able to easily
find out which objects are functions.

The function below (listfunc()) works fine. I'm just asking this for future
reference.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
listfunc <- function() { 
# lists names of all function objects in the global environment 
obj <- objects(.GlobalEnv) 
funclist <- character(length = 0) 
for (i in 1:length(obj)) { 
? ? if (mode(get(obj[i])) == "function") funclist <-
c(funclist,obj[i])
? } 
return(funclist) 
}
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Tena koe Byron

Many years ago, I came across the following function by Simon Fear:

function (splitby = mode, pos = 1, ...) 
{
    lsout <- ls(pos = pos, ...)
    tapply(lsout, sapply(lsout, function(x) {
        splitby(get(x))
    }), invisible)
}

from which one can deduce that, given your obj, the following line could replace
your loop:

obj[sapply(obj, function(x) mode(get(x))=='function')]

For future reference, it can be slow in R to  continually append to an object:

test <- character(0)
system.time(for (i in 1:10^5) test <- c(test, as.character(i)))
#   user  system elapsed 
#  47.86    0.02   47.89 
test <- character(10^5)
system.time(for (i in 1:10^5) test[i] <- as.character(i))
#   user  system elapsed 
#   0.25    0.00    0.25

HTH ....

Peter Alspach
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Byron Dom
Sent: Monday, 19 May 2014 10:50 a.m.
To: "r-help at r-project.org"
Subject: [R] Is there an easier way than this to list all functions in the
global environment?



After an unsuccessful search thru several books plus online documentation, I was
unable to find a simple way to do this, so I wrote my own function (see below)
to do it. ?I'm relatively new to R however, so I'm guessing that there
must be an easier way to do it.

I want to list all functions and only the functions (not other objects also) in
the global environment.

I'm working with several old R workspaces that contain a very large number
of objects -- functions, data structures, etc. and I would to be able to easily
find out which objects are functions.

The function below (listfunc()) works fine. I'm just asking this for future
reference.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
listfunc <- function() {
# lists names of all function objects in the global environment obj <-
objects(.GlobalEnv) funclist <- character(length = 0) for (i in
1:length(obj)) {
? ? if (mode(get(obj[i])) == "function") funclist <-
c(funclist,obj[i])
? }
return(funclist)
}
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

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