Re: [R] try-error can not be test. Why?
On 08/09/2010 11:46 PM, Philippe Grosjean wrote: On 08/09/10 19:25, David Winsemius wrote: On Sep 8, 2010, at 1:18 PM, telm8 wrote: Hi, I am having some strange problem with detecting try-error. From what I have read so far the following statement: try( log(a) ) == try-error should yield TRUE, however, it yields FALSE. I can not figure out why. Can someone help? class(try( log(a), silent=TRUE )) == try-error [1] TRUE This is perfectly correct in this case, but while we are mentioning a test on the class of an object, the better syntax is: inherits(try(log(a)), try-error) In a more general context, class may be defined with multiple strings (R way of subclassing S3 objects). For instance, this does not work: if (class(Sys.time()) == POSIXct) ok else not ok ... because the class of a `POSIXct' object is defined as: c(POSIXt, POSIXct). This works: Getting even further off track: another advantage of inherits() is that the class can change. For example, in the upcoming 2.12.0 release, the class of Sys.time() will be class(Sys.time()) [1] POSIXct POSIXt Putting the names in the reverse order was a relic from ancient times that will soon be corrected. The tests below won't care about this change, but some more fragile tests might. Duncan Murdoch if (inherits(Sys.time(), POSIXct)) ok else not ok Alternate valid tests would be (but a little bit less readable): if (any(class(Sys.time()) == POSIXct)) ok else not ok or, by installing the operators package, a less conventional, but cleaner code: install.packages(operators) library(operators) if (Sys.time() %of% POSIXct) ok else not ok Best, Philippe Grosjean Many thanks -- View this message in context: http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531675.html Sent from the R help mailing list archive at Nabble.com. __ 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. David Winsemius, MD West Hartford, CT __ 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. __ 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. __ 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.
[R] try-error can not be test. Why?
Hi, I am having some strange problem with detecting try-error. From what I have read so far the following statement: try( log(a) ) == try-error should yield TRUE, however, it yields FALSE. I can not figure out why. Can someone help? Many thanks -- View this message in context: http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531675.html Sent from the R help mailing list archive at Nabble.com. __ 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] try-error can not be test. Why?
On Sep 8, 2010, at 1:18 PM, telm8 wrote: Hi, I am having some strange problem with detecting try-error. From what I have read so far the following statement: try( log(a) ) == try-error should yield TRUE, however, it yields FALSE. I can not figure out why. Can someone help? class(try( log(a), silent=TRUE )) == try-error [1] TRUE Many thanks -- View this message in context: http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531675.html Sent from the R help mailing list archive at Nabble.com. __ 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. David Winsemius, MD West Hartford, CT __ 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] try-error can not be test. Why?
Thank worked! Thank you so much!!! -- View this message in context: http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531726.html Sent from the R help mailing list archive at Nabble.com. __ 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] try-error can not be test. Why?
On 08/09/10 19:25, David Winsemius wrote: On Sep 8, 2010, at 1:18 PM, telm8 wrote: Hi, I am having some strange problem with detecting try-error. From what I have read so far the following statement: try( log(a) ) == try-error should yield TRUE, however, it yields FALSE. I can not figure out why. Can someone help? class(try( log(a), silent=TRUE )) == try-error [1] TRUE This is perfectly correct in this case, but while we are mentioning a test on the class of an object, the better syntax is: inherits(try(log(a)), try-error) In a more general context, class may be defined with multiple strings (R way of subclassing S3 objects). For instance, this does not work: if (class(Sys.time()) == POSIXct) ok else not ok ... because the class of a `POSIXct' object is defined as: c(POSIXt, POSIXct). This works: if (inherits(Sys.time(), POSIXct)) ok else not ok Alternate valid tests would be (but a little bit less readable): if (any(class(Sys.time()) == POSIXct)) ok else not ok or, by installing the operators package, a less conventional, but cleaner code: install.packages(operators) library(operators) if (Sys.time() %of% POSIXct) ok else not ok Best, Philippe Grosjean Many thanks -- View this message in context: http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531675.html Sent from the R help mailing list archive at Nabble.com. __ 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. David Winsemius, MD West Hartford, CT __ 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. __ 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] try-error can not be test. Why?
On Sep 8, 2010, at 11:46 PM, Philippe Grosjean wrote:
On 08/09/10 19:25, David Winsemius wrote:
On Sep 8, 2010, at 1:18 PM, telm8 wrote:
Hi,
I am having some strange problem with detecting try-error. From
what I
have read so far the following statement:
try( log(a) ) == try-error
should yield TRUE, however, it yields FALSE. I can not figure out
why.
Can
someone help?
class(try( log(a), silent=TRUE )) == try-error
[1] TRUE
This is perfectly correct in this case, but while we are mentioning
a test on the class of an object, the better syntax is:
inherits(try(log(a)), try-error)
In a more general context, class may be defined with multiple
strings (R way of subclassing S3 objects). For instance, this does
not work:
if (class(Sys.time()) == POSIXct) ok else not ok
... because the class of a `POSIXct' object is defined as:
c(POSIXt, POSIXct). This works:
if (inherits(Sys.time(), POSIXct)) ok else not ok
Alternate valid tests would be (but a little bit less readable):
if (any(class(Sys.time()) == POSIXct)) ok else not ok
or, by installing the operators package, a less conventional, but
cleaner code:
install.packages(operators)
library(operators)
if (Sys.time() %of% POSIXct) ok else not ok
I have also used if (try-error %in% class(try(log(a))) ) { } else
{ }, but the inherits() form looks at the very least less clunky.
Best,
Philippe Grosjean
Many thanks
--
View this message in context:
http://r.789695.n4.nabble.com/try-error-can-not-be-test-Why-tp2531675p2531675.html
Sent from the R help mailing list archive at Nabble.com.
__
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.
David Winsemius, MD
West Hartford, CT
__
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.
__
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.
