R help - Dec 2009 - What is the function to test if a vector is ordered or not?

I did a search on www.rseek.org to look for the function to test if a
vector is ordered or not. But I don't find it. Could somebody let me
know what function I should use?

On Dec 9, 2009, at 10:10 PM, Peng Yu wrote:
> I did a search on www.rseek.org to look for the function to test if a
> vector is ordered or not. But I don't find it. Could somebody let me
> know what function I should use?

If by ordered, you mean sorted, then ?is.unsorted

 > is.unsorted(c(1, 4, 2, 6, 7))
[1] TRUE

 > is.unsorted(sort(c(1, 4, 2, 6, 7)))
[1] FALSE


If you mean to test a factor to see if it is an ordered factor, then ? 
is.ordered

 > is.ordered(factor(letters))
[1] FALSE

 > is.ordered(factor(letters, ordered = TRUE))
[1] TRUE


HTH,

Marc Schwartz

Try

all(diff(order(yourVector)) == 1)

On Wed, Dec 9, 2009 at 10:10 PM, Peng Yu <pengyu.ut@gmail.com> wrote:
> I did a search on www.rseek.org to look for the function to test if a
> vector is ordered or not. But I don't find it. Could somebody let me
> know what function I should use?
>
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http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
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>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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