Re: [R] finding numbers in a range

[David Winsemius]

On Jun 1, 2011, at 5:07 PM, Salih Tuna wrote:
Hi,
Is there a quick way of finding if numbers in a vector falls in  
between a
range defined in another matrix.
As an example let
x   y
0      1   3
2      6   9
25    15  18

I want to check one by one whether 0,2 and 25 falls in any of the  
ranges in
y.
I am using 2 for loops but it is taking a huge amount of time.
is there any other alternative way to do this?

If this represents the full complexity of the problem then  
findInterval would work:

> findInterval(c(0,2,25), c(1,3,6,9,15,18) ) %in% c(1,3,5)
[1] FALSE  TRUE FALSE

On the other hand if the y intervals overlap then a different method  
may be needed.

> sapply( c(0, 2, 25) , function(x) {any( y[,1] < x & x < y[,2]) })
[1] FALSE  TRUE FALSE

--
David Winsemius, MD
West Hartford, CT

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