[R] Check the class of an object
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I found
out, that 'is' cannot test for a specific class, as also inherited classes can
be treated as their super classes. I need to do checks for specific classes.
What I do right now is sth. like
if (class(myClass) == firstClass) {
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R? I was expecting some
specific method (and 'inherits' or 'extends' is not what I look for)...
Best
Simon
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Re: [R] Check the class of an object
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I found
out, that 'is' cannot test for a specific class, as also inherited classes
can be treated as their super classes. I need to do checks for specific
classes. What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in those
instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not what
I look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
Re: [R] Check the class of an object
Hi David,
thanks for the reply. You are right. Using the %in% is more stable and I gonna
change my code.
When testing for a specific class using 'is' one has to start at the lowest
heir and walk up the inheritance structure. Starting at the checks at the root
will always give TRUE. Having a structure which is quite complicated let me
move to the check I suggested in my first mail.
Best
Simon
On Jul 23, 2013, at 6:15 PM, David Winsemius dwinsem...@comcast.net wrote:
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I
found out, that 'is' cannot test for a specific class, as also inherited
classes can be treated as their super classes. I need to do checks for
specific classes. What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in
those instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not
what I look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
Re: [R] Check the class of an object
On 07/23/2013 09:59 AM, Simon Zehnder wrote:
Hi David,
thanks for the reply. You are right. Using the %in% is more stable and I gonna
change my code.
you said you were you were using S4 classes. S4 classes do not report vectors of
length != 1, from ?class
For objects which have a formal class, its name is returned by 'class'
as a character vector of length one
so a first unit test could be
stopifnot(length(class(myObject)) != 1L)
When testing for a specific class using 'is' one has to start at the lowest
heir and walk up the inheritance structure. Starting at the checks at the root
will always give TRUE. Having a structure which is quite complicated let me
move to the check I suggested in my first mail.
Best
Simon
On Jul 23, 2013, at 6:15 PM, David Winsemius dwinsem...@comcast.net wrote:
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I found
out, that 'is' cannot test for a specific class, as also inherited classes can
be treated as their super classes. I need to do checks for specific classes.
What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in those
instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not what I
look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
--
Computational Biology / Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N.
PO Box 19024 Seattle, WA 98109
Location: Arnold Building M1 B861
Phone: (206) 667-2793
__
R-help@r-project.org mailing list
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.
Re: [R] Check the class of an object
Hi,
On 07/23/2013 09:59 AM, Simon Zehnder wrote:
Hi David,
thanks for the reply. You are right. Using the %in% is more stable and I gonna
change my code.
Unlike with S3 objects, class() on an S4 object can only return 1 class.
Also note that, on an S3 object, doing
firstClass %in% class(myObject)
is equivalent to doing inherits(myObject, firstClass), which is
what you said you wanted to avoid. The most specific class should be
the first so if that's what you wanted to check, you could do
class(myObject)[1] == firstClass
But that precaution is not needed if 'myObject' is guaranteed to be
an S4 object (although when writing a unit test, one should probably
discard any guarantee of that sort).
Cheers,
H.
When testing for a specific class using 'is' one has to start at the lowest
heir and walk up the inheritance structure. Starting at the checks at the root
will always give TRUE. Having a structure which is quite complicated let me
move to the check I suggested in my first mail.
Best
Simon
On Jul 23, 2013, at 6:15 PM, David Winsemius dwinsem...@comcast.net wrote:
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I found
out, that 'is' cannot test for a specific class, as also inherited classes can
be treated as their super classes. I need to do checks for specific classes.
What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in those
instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not what I
look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpa...@fhcrc.org
Phone: (206) 667-5791
Fax:(206) 667-1319
__
R-help@r-project.org mailing list
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.
Re: [R] Check the class of an object
Hi Martin,
I didn't know that. But that is even more comfortable for checking. Thanks for
the quick update!
Best
Simon
P.S. And thanks for the online documents about S4 - I could already learn a lot!
On Jul 23, 2013, at 7:11 PM, Martin Morgan mtmor...@fhcrc.org wrote:
On 07/23/2013 09:59 AM, Simon Zehnder wrote:
Hi David,
thanks for the reply. You are right. Using the %in% is more stable and I
gonna change my code.
you said you were you were using S4 classes. S4 classes do not report vectors
of length != 1, from ?class
For objects which have a formal class, its name is returned by 'class'
as a character vector of length one
so a first unit test could be
stopifnot(length(class(myObject)) != 1L)
When testing for a specific class using 'is' one has to start at the lowest
heir and walk up the inheritance structure. Starting at the checks at the
root will always give TRUE. Having a structure which is quite complicated
let me move to the check I suggested in my first mail.
Best
Simon
On Jul 23, 2013, at 6:15 PM, David Winsemius dwinsem...@comcast.net wrote:
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I
found out, that 'is' cannot test for a specific class, as also inherited
classes can be treated as their super classes. I need to do checks for
specific classes. What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in
those instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not
what I look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
--
Computational Biology / Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N.
PO Box 19024 Seattle, WA 98109
Location: Arnold Building M1 B861
Phone: (206) 667-2793
__
R-help@r-project.org mailing list
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.
Re: [R] Check the class of an object
Hi Hervé,
thank you very much for your reply! This makes the different treatment of S3
and S4 objects by 'class' clear.
Best
Simon
On Jul 23, 2013, at 7:20 PM, Hervé Pagès hpa...@fhcrc.org wrote:
Hi,
On 07/23/2013 09:59 AM, Simon Zehnder wrote:
Hi David,
thanks for the reply. You are right. Using the %in% is more stable and I
gonna change my code.
Unlike with S3 objects, class() on an S4 object can only return 1 class.
Also note that, on an S3 object, doing
firstClass %in% class(myObject)
is equivalent to doing inherits(myObject, firstClass), which is
what you said you wanted to avoid. The most specific class should be
the first so if that's what you wanted to check, you could do
class(myObject)[1] == firstClass
But that precaution is not needed if 'myObject' is guaranteed to be
an S4 object (although when writing a unit test, one should probably
discard any guarantee of that sort).
Cheers,
H.
When testing for a specific class using 'is' one has to start at the lowest
heir and walk up the inheritance structure. Starting at the checks at the
root will always give TRUE. Having a structure which is quite complicated
let me move to the check I suggested in my first mail.
Best
Simon
On Jul 23, 2013, at 6:15 PM, David Winsemius dwinsem...@comcast.net wrote:
On Jul 23, 2013, at 5:36 AM, Simon Zehnder wrote:
Dear R-Users and R-Devels,
I have large project based on S4 classes. While writing my unit tests I
found out, that 'is' cannot test for a specific class, as also inherited
classes can be treated as their super classes. I need to do checks for
specific classes. What I do right now is sth. like
if (class(myClass) == firstClass) {
I would think that you would need to use `%in%` instead.
if( firstClass %in% class(myObject) ){
Objects can have more than one class, so testing with == would fail in
those instances.
} else if (class(myClass) == secondClass) {
}
Is this the usual way how classes are checked in R?
Well, `inherits` IS the usual way.
I was expecting some specific method (and 'inherits' or 'extends' is not
what I look for)...
Best
Simon
[[alternative HTML version deleted]]
Plain-text format is the recommended format for Rhelp
--
David Winsemius
Alameda, CA, USA
__
R-help@r-project.org mailing list
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.
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpa...@fhcrc.org
Phone: (206) 667-5791
Fax:(206) 667-1319
__
R-help@r-project.org mailing list
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.
