Suppose I have the following list:
test <- list(a=3,b=5,c=11)
I'm trying to figure out how to extract the characters to the left of
the equal sign (i.e., I want to extract a list of the variable names, a,
b and c.
I've tried the permutations I know of involving sub - things like
sub("\\=.*", "", test), but no matter what I try, sub keeps
returning
(3, 5, 11). In other words, even though I'm trying to extract the
'stuff' before the = sign, I seem to be successful only at grabbing the
stuff after the equal sign.
Pointers to the obvious fix? Thanks...
You probably want `names(test)`. On Thu, May 25, 2023 at 7:58?PM Evan Cooch <evan.cooch at gmail.com> wrote:> Suppose I have the following list: > > test <- list(a=3,b=5,c=11) > > I'm trying to figure out how to extract the characters to the left of > the equal sign (i.e., I want to extract a list of the variable names, a, > b and c. > > I've tried the permutations I know of involving sub - things like > sub("\\=.*", "", test), but no matter what I try, sub keeps returning > (3, 5, 11). In other words, even though I'm trying to extract the > 'stuff' before the = sign, I seem to be successful only at grabbing the > stuff after the equal sign. > > Pointers to the obvious fix? Thanks... > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]
On Thu, 25 May 2023 13:29:52 -0400 Evan Cooch <evan.cooch at gmail.com> wrote:> Suppose I have the following list: > > test <- list(a=3,b=5,c=11) > > I'm trying to figure out how to extract the characters to the left of > the equal sign (i.e., I want to extract a list of the variable names, > a, b and c. > > I've tried the permutations I know of involving sub - things like > sub("\\=.*", "", test), but no matter what I try, sub keeps returning > (3, 5, 11). In other words, even though I'm trying to extract the > 'stuff' before the = sign, I seem to be successful only at grabbing > the stuff after the equal sign. > > Pointers to the obvious fix? Thanks...Perhaps names(test) ??? cheers, Rolf Turner -- Honorary Research Fellow Department of Statistics University of Auckland Stats. Dep't. (secretaries) phone: +64-9-373-7599 ext. 89622 Home phone: +64-9-480-4619
@vi@e@gross m@iii@g oii gm@ii@com
2023-May-26 01:17 UTC
[R] extract parts of a list before symbol
Evan, List names are less easy than data.frame column names so try this:> test <- list(a=3,b=5,c=11) > colnames(test)NULL> colnames(as.data.frame(test))[1] "a" "b" "c" But note an entry with no name has one made up for it.> test2 <- list(a=3,b=5, 666, c=11) > colnames(data.frame(test2))[1] "a" "b" "X666" "c" But that may be overkill as simply converting to a vector if ALL parts are of the same type will work too:> names(as.vector(test))[1] "a" "b" "c" To get one at a time:> names(as.vector(test))[1][1] "a" You can do it even simple by looking at the attributes of your list:> attributes(test)$names [1] "a" "b" "c"> attributes(test)$names[1] "a" "b" "c"> attributes(test)$names[3][1] "c" -----Original Message----- From: R-help <r-help-bounces at r-project.org> On Behalf Of Evan Cooch Sent: Thursday, May 25, 2023 1:30 PM To: r-help at r-project.org Subject: [R] extract parts of a list before symbol Suppose I have the following list: test <- list(a=3,b=5,c=11) I'm trying to figure out how to extract the characters to the left of the equal sign (i.e., I want to extract a list of the variable names, a, b and c. I've tried the permutations I know of involving sub - things like sub("\\=.*", "", test), but no matter what I try, sub keeps returning (3, 5, 11). In other words, even though I'm trying to extract the 'stuff' before the = sign, I seem to be successful only at grabbing the stuff after the equal sign. Pointers to the obvious fix? Thanks... ______________________________________________ R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.