R help - Nov 2011 - length of empty string

Hi all,

 

Can somebody explain why length("") returns 1 and not 0? How do I test
if a given string is the empty string?

 

Thanks,

Steffen.





 


	[[alternative HTML version deleted]]

Le vendredi 18 novembre 2011 ? 16:09 +0100, Jaensch, Steffen [TIBBE] a
?crit :
> Hi all,
>
> Can somebody explain why length("") returns 1 and not 0?
Probably because it contains one element, "".
> How do I test if a given string is the empty string?
a <- ""
a == ""
[1] TRUE

Seems to be enough to me. ;-)


Cheers

On Nov 18, 2011, at 10:09 AM, Jaensch, Steffen [TIBBE] wrote:
> Hi all,
>
>
>
> Can somebody explain why length("") returns 1 and not 0? How do I
test
> if a given string is the empty string?
character(0) is not the same as ""


-- 

David Winsemius, MD
West Hartford, CT

> nchar("")
[1] 0 


On Friday 18 November 2011 16:09:38 Jaensch, Steffen [TIBBE]
wrote:
> Hi all,
> 
> 
> 
> Can somebody explain why length("") returns 1 and not 0? How do I
test
> if a given string is the empty string?
> 
> 
> 
> Thanks,
> 
> Steffen.
> 
> 
> 
> 
> 
> 
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.

Because it's a character vector with only one element, which just happens to
be empty - sort of like why the cardinality of the set { /O } is one. (/O being
my best shot at the empty set symbol in plain text).

You might be thinking of nchar(). 

Michael

On Nov 18, 2011, at 10:09 AM, "Jaensch, Steffen [TIBBE]" <SJAENSCH
at its.jnj.com> wrote:
> Hi all,
> 
> 
> 
> Can somebody explain why length("") returns 1 and not 0? How do I
test
> if a given string is the empty string?
> 
> 
> 
> Thanks,
> 
> Steffen.
> 
> 
> 
> 
> 
> 
> 
> 
>    [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.