How to check if object (variable) is defined in R?
226
I'd like to check if some variable is defined in R - without getting an error. How can I do this?
My attempts (not successful):
> is.na(ooxx)
Error: object 'ooxx' not found
> is.finite(ooxx)
Error: object 'ooxx' not found
Thanks!
r
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
add a comment |
226
I'd like to check if some variable is defined in R - without getting an error. How can I do this?
My attempts (not successful):
> is.na(ooxx)
Error: object 'ooxx' not found
> is.finite(ooxx)
Error: object 'ooxx' not found
Thanks!
r
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
add a comment |
226
226
226
28
I'd like to check if some variable is defined in R - without getting an error. How can I do this?
My attempts (not successful):
> is.na(ooxx)
Error: object 'ooxx' not found
> is.finite(ooxx)
Error: object 'ooxx' not found
Thanks!
r
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
I'd like to check if some variable is defined in R - without getting an error. How can I do this?
My attempts (not successful):
> is.na(ooxx)
Error: object 'ooxx' not found
> is.finite(ooxx)
Error: object 'ooxx' not found
Thanks!
r
r
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
edited Jun 1 '16 at 14:16
TMS
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
asked Feb 20 '12 at 21:46
TMSTMS
34k37172305
34k37172305
add a comment |
add a comment |
5 Answers
5
active
oldest
votes
370
You want exists():
R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
add a comment |
95
See ?exists, for some definition of "...is defined". E.g.
> exists("foo")
[1] FALSE
> foo <- 1:10
> exists("foo")
[1] TRUE
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
add a comment |
53
if you are inside a function, missing() is what you want.
exchequer = function(x) {
if(missing(x)){
message("x is missing… :-(")
}
}
exchequer()
x is missing… :-(
answered Mar 9 '13 at 21:56
timtim
1,9201734
missingonly works for function arguments, however. You can't dofoo <- function(x) {missing(x); missing(y)}or you will getfoo(1)> Error in missing(y) : 'missing' can only be used for arguments.
– Dannid
Feb 11 at 17:48
add a comment |
38
As others have pointed out, you're looking for exists. Keep in mind that using exists with names used by R's base packages would return true regardless of whether you defined the variable:
> exists("data")
[1] TRUE
To get around this (as pointed out by Bazz; see ?exists), use the inherits argument:
> exists("data", inherits = FALSE)
[1] FALSE
foo <- TRUE
> exists("foo", inherits = FALSE)
[1] TRUE
Of course, if you wanted to search the name spaces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in base packages -- is the following:
any(sapply(1:(which(search() == "tools:rstudio") - 1L),
function(pp) exists(_object_name_, where = pp, inherits = FALSE)))
Compare replacing _object_name_ with "data.table" (TRUE) vs. "var" (FALSE)
(of course, if you're not on RStudio, I think the first automatically attached environment is "package:stats")
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
1
Playing around, using argumentinherits = FALSEseems to isolate things in the global environment. Does that sound right?
– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
add a comment |
16
If you don't want to use quotes, you can use deparse(substitute()) trick which I found in example section of ?substitute:
is.defined <- function(sym) {
sym <- deparse(substitute(sym))
env <- parent.frame()
exists(sym, env)
}
is.defined(a)
# FALSE
a <- 10
is.defined(a)
# TRUE
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can alsoforceor evaluate it in the function like this:is.defined <- function(sym) class(try(sym, TRUE))!='try-error'
– chinsoon12
Oct 4 '17 at 0:49
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f9368900%2fhow-to-check-if-object-variable-is-defined-in-r%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
5 Answers
5
active
oldest
votes
5 Answers
5
active
oldest
votes
active
oldest
votes
active
oldest
votes
370
You want exists():
R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
add a comment |
370
You want exists():
R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
add a comment |
370
370
370
You want exists():
R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
You want exists():
R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
answered Feb 20 '12 at 21:51
Dirk EddelbuettelDirk Eddelbuettel
281k38519606
281k38519606
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
add a comment |
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
1
1
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
@Gavin & Dirk, you're so nice to each other :) Only solution is that you toss the coin (Bernoulli with p=0.5 :-)) who will get the accept! :-)
– TMS
Feb 20 '12 at 22:00
25
25
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
@tim if you are inside a function, missing() is what you want.
– CousinCocaine
Jan 27 '14 at 14:31
2
2
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
Might get a bit trickier if checking for list elements: stackoverflow.com/q/7719741
– TMS
Sep 20 '14 at 11:58
3
3
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
what about for what the op wanted - using the variable name, not in quotes?
– tim
Jun 13 '15 at 13:46
add a comment |
95
See ?exists, for some definition of "...is defined". E.g.
> exists("foo")
[1] FALSE
> foo <- 1:10
> exists("foo")
[1] TRUE
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
add a comment |
95
See ?exists, for some definition of "...is defined". E.g.
> exists("foo")
[1] FALSE
> foo <- 1:10
> exists("foo")
[1] TRUE
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
add a comment |
95
95
95
See ?exists, for some definition of "...is defined". E.g.
> exists("foo")
[1] FALSE
> foo <- 1:10
> exists("foo")
[1] TRUE
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
See ?exists, for some definition of "...is defined". E.g.
> exists("foo")
[1] FALSE
> foo <- 1:10
> exists("foo")
[1] TRUE
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
answered Feb 20 '12 at 21:50
Gavin SimpsonGavin Simpson
137k19314389
137k19314389
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
add a comment |
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
7
7
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
You win by 52 seconds :)
– Dirk Eddelbuettel
Feb 20 '12 at 21:51
7
7
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
@DirkEddelbuettel Well, if you will use ridiculously long object names ;-)
– Gavin Simpson
Feb 20 '12 at 21:54
2
2
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
heh. Happens to me all the time when I am testing out examples before posting, Gavin or Josh have already answered it.
– Maiasaura
Feb 20 '12 at 22:17
add a comment |
53
if you are inside a function, missing() is what you want.
exchequer = function(x) {
if(missing(x)){
message("x is missing… :-(")
}
}
exchequer()
x is missing… :-(
answered Mar 9 '13 at 21:56
timtim
1,9201734
missingonly works for function arguments, however. You can't dofoo <- function(x) {missing(x); missing(y)}or you will getfoo(1)> Error in missing(y) : 'missing' can only be used for arguments.
– Dannid
Feb 11 at 17:48
add a comment |
53
if you are inside a function, missing() is what you want.
exchequer = function(x) {
if(missing(x)){
message("x is missing… :-(")
}
}
exchequer()
x is missing… :-(
answered Mar 9 '13 at 21:56
timtim
1,9201734
missingonly works for function arguments, however. You can't dofoo <- function(x) {missing(x); missing(y)}or you will getfoo(1)> Error in missing(y) : 'missing' can only be used for arguments.
– Dannid
Feb 11 at 17:48
add a comment |
53
53
53
if you are inside a function, missing() is what you want.
exchequer = function(x) {
if(missing(x)){
message("x is missing… :-(")
}
}
exchequer()
x is missing… :-(
answered Mar 9 '13 at 21:56
timtim
1,9201734
if you are inside a function, missing() is what you want.
exchequer = function(x) {
if(missing(x)){
message("x is missing… :-(")
}
}
exchequer()
x is missing… :-(
answered Mar 9 '13 at 21:56
timtim
1,9201734
answered Mar 9 '13 at 21:56
timtim
1,9201734
answered Mar 9 '13 at 21:56
timtim
1,9201734
answered Mar 9 '13 at 21:56
timtim
1,9201734
1,9201734
missingonly works for function arguments, however. You can't dofoo <- function(x) {missing(x); missing(y)}or you will getfoo(1)> Error in missing(y) : 'missing' can only be used for arguments.
– Dannid
Feb 11 at 17:48
add a comment |
missingonly works for function arguments, however. You can't dofoo <- function(x) {missing(x); missing(y)}or you will getfoo(1)> Error in missing(y) : 'missing' can only be used for arguments.
– Dannid
Feb 11 at 17:48
missing only works for function arguments, however. You can't do foo <- function(x) {missing(x); missing(y)} or you will get foo(1) > Error in missing(y) : 'missing' can only be used for arguments.– Dannid
Feb 11 at 17:48
missing only works for function arguments, however. You can't do foo <- function(x) {missing(x); missing(y)} or you will get foo(1) > Error in missing(y) : 'missing' can only be used for arguments.– Dannid
Feb 11 at 17:48
add a comment |
38
As others have pointed out, you're looking for exists. Keep in mind that using exists with names used by R's base packages would return true regardless of whether you defined the variable:
> exists("data")
[1] TRUE
To get around this (as pointed out by Bazz; see ?exists), use the inherits argument:
> exists("data", inherits = FALSE)
[1] FALSE
foo <- TRUE
> exists("foo", inherits = FALSE)
[1] TRUE
Of course, if you wanted to search the name spaces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in base packages -- is the following:
any(sapply(1:(which(search() == "tools:rstudio") - 1L),
function(pp) exists(_object_name_, where = pp, inherits = FALSE)))
Compare replacing _object_name_ with "data.table" (TRUE) vs. "var" (FALSE)
(of course, if you're not on RStudio, I think the first automatically attached environment is "package:stats")
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
1
Playing around, using argumentinherits = FALSEseems to isolate things in the global environment. Does that sound right?
– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
add a comment |
38
As others have pointed out, you're looking for exists. Keep in mind that using exists with names used by R's base packages would return true regardless of whether you defined the variable:
> exists("data")
[1] TRUE
To get around this (as pointed out by Bazz; see ?exists), use the inherits argument:
> exists("data", inherits = FALSE)
[1] FALSE
foo <- TRUE
> exists("foo", inherits = FALSE)
[1] TRUE
Of course, if you wanted to search the name spaces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in base packages -- is the following:
any(sapply(1:(which(search() == "tools:rstudio") - 1L),
function(pp) exists(_object_name_, where = pp, inherits = FALSE)))
Compare replacing _object_name_ with "data.table" (TRUE) vs. "var" (FALSE)
(of course, if you're not on RStudio, I think the first automatically attached environment is "package:stats")
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
1
Playing around, using argumentinherits = FALSEseems to isolate things in the global environment. Does that sound right?
– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
add a comment |
38
38
38
As others have pointed out, you're looking for exists. Keep in mind that using exists with names used by R's base packages would return true regardless of whether you defined the variable:
> exists("data")
[1] TRUE
To get around this (as pointed out by Bazz; see ?exists), use the inherits argument:
> exists("data", inherits = FALSE)
[1] FALSE
foo <- TRUE
> exists("foo", inherits = FALSE)
[1] TRUE
Of course, if you wanted to search the name spaces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in base packages -- is the following:
any(sapply(1:(which(search() == "tools:rstudio") - 1L),
function(pp) exists(_object_name_, where = pp, inherits = FALSE)))
Compare replacing _object_name_ with "data.table" (TRUE) vs. "var" (FALSE)
(of course, if you're not on RStudio, I think the first automatically attached environment is "package:stats")
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
As others have pointed out, you're looking for exists. Keep in mind that using exists with names used by R's base packages would return true regardless of whether you defined the variable:
> exists("data")
[1] TRUE
To get around this (as pointed out by Bazz; see ?exists), use the inherits argument:
> exists("data", inherits = FALSE)
[1] FALSE
foo <- TRUE
> exists("foo", inherits = FALSE)
[1] TRUE
Of course, if you wanted to search the name spaces of attached packages, this would also fall short:
> exists("data.table")
[1] FALSE
require(data.table)
> exists("data.table", inherits = FALSE)
[1] FALSE
> exists("data.table")
[1] TRUE
The only thing I can think of to get around this -- to search in attached packages but not in base packages -- is the following:
any(sapply(1:(which(search() == "tools:rstudio") - 1L),
function(pp) exists(_object_name_, where = pp, inherits = FALSE)))
Compare replacing _object_name_ with "data.table" (TRUE) vs. "var" (FALSE)
(of course, if you're not on RStudio, I think the first automatically attached environment is "package:stats")
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
edited Feb 3 '16 at 3:37
MichaelChirico
20.5k863117
20.5k863117
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
answered Sep 24 '15 at 16:19
Santiago BaldrichSantiago Baldrich
563511
563511
1
Playing around, using argumentinherits = FALSEseems to isolate things in the global environment. Does that sound right?
– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
add a comment |
1
Playing around, using argumentinherits = FALSEseems to isolate things in the global environment. Does that sound right?
– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
1
1
Playing around, using argument
inherits = FALSE seems to isolate things in the global environment. Does that sound right?– CJB
Jan 7 '16 at 12:49
Playing around, using argument
inherits = FALSE seems to isolate things in the global environment. Does that sound right?– CJB
Jan 7 '16 at 12:49
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
@Bazz you're correct; I've edited this into the answer.
– MichaelChirico
Feb 3 '16 at 3:21
1
1
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
This comment should be higher up, since I use variable name "data", just using exist gave me some trouble initially.
– mzm
May 11 '16 at 14:44
add a comment |
16
If you don't want to use quotes, you can use deparse(substitute()) trick which I found in example section of ?substitute:
is.defined <- function(sym) {
sym <- deparse(substitute(sym))
env <- parent.frame()
exists(sym, env)
}
is.defined(a)
# FALSE
a <- 10
is.defined(a)
# TRUE
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can alsoforceor evaluate it in the function like this:is.defined <- function(sym) class(try(sym, TRUE))!='try-error'
– chinsoon12
Oct 4 '17 at 0:49
add a comment |
16
If you don't want to use quotes, you can use deparse(substitute()) trick which I found in example section of ?substitute:
is.defined <- function(sym) {
sym <- deparse(substitute(sym))
env <- parent.frame()
exists(sym, env)
}
is.defined(a)
# FALSE
a <- 10
is.defined(a)
# TRUE
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can alsoforceor evaluate it in the function like this:is.defined <- function(sym) class(try(sym, TRUE))!='try-error'
– chinsoon12
Oct 4 '17 at 0:49
add a comment |
16
16
16
If you don't want to use quotes, you can use deparse(substitute()) trick which I found in example section of ?substitute:
is.defined <- function(sym) {
sym <- deparse(substitute(sym))
env <- parent.frame()
exists(sym, env)
}
is.defined(a)
# FALSE
a <- 10
is.defined(a)
# TRUE
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
If you don't want to use quotes, you can use deparse(substitute()) trick which I found in example section of ?substitute:
is.defined <- function(sym) {
sym <- deparse(substitute(sym))
env <- parent.frame()
exists(sym, env)
}
is.defined(a)
# FALSE
a <- 10
is.defined(a)
# TRUE
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
edited Apr 17 '17 at 8:40
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
answered Apr 17 '17 at 6:32
NirmalNirmal
31125
31125
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can alsoforceor evaluate it in the function like this:is.defined <- function(sym) class(try(sym, TRUE))!='try-error'
– chinsoon12
Oct 4 '17 at 0:49
add a comment |
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can alsoforceor evaluate it in the function like this:is.defined <- function(sym) class(try(sym, TRUE))!='try-error'
– chinsoon12
Oct 4 '17 at 0:49
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
I wish people knew how sick this was. Good work.
– Carl Boneri
Jun 27 '17 at 18:36
you can also
force or evaluate it in the function like this: is.defined <- function(sym) class(try(sym, TRUE))!='try-error'– chinsoon12
Oct 4 '17 at 0:49
you can also
force or evaluate it in the function like this: is.defined <- function(sym) class(try(sym, TRUE))!='try-error'– chinsoon12
Oct 4 '17 at 0:49
add a comment |
draft saved
draft discarded
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f9368900%2fhow-to-check-if-object-variable-is-defined-in-r%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
