[R] test whether all elements of a vector are identical

[David Winsemius]

On Dec 16, 2010, at 10:19 AM, David Winsemius wrote:

>
> On Dec 16, 2010, at 9:56 AM, baptiste auguie wrote:
>
>> Hi,
>>
>> The fastest way seems to be,
>>
>> all(x[1] == x)
>
> I'm sure that is more efficient than this methods:
>
> patt <- paste("^",x[1],"$", sep="")
> length( grep(patt, x) == length(x) )
>
Wrong position of closing paren:

 > length( grep(patt, x)) == length(x)
[1] TRUE

> ... but sometimes it helps to have strategies that might generalize  
> to notions of "begins with" or "ends with" rather than "identical".
>
> -- 
> David.
>>
>>
>> HTH,
>>
>> baptiste
>>
>> On 16 December 2010 15:17, Jannis <bt_jannis at yahoo.de> wrote:
>>> Dear list,
>>>
>>>
>>> this might be an easy one, but I could figure out a solution (or  
>>> how to
>>> google the right term).
>>>
>>> Is there any way to test whether all elements of a vector are  
>>> identical?
>>>
>>> For numeric vectors I would use
>>>
>>> sum(diff(vector)==0)==0
>>>
>>> but I have character vectors. Any Ideas?
>>>
>>> Cheers
>>> Jannis
>>>
>>> ______________________________________________
>>> 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.
>>>
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> West Hartford, CT
>
> ______________________________________________
> 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.

David Winsemius, MD
West Hartford, CT