R help - Feb 2011 - does range of values in array include a third value?

I'm using the range command to get the minimum and maximum values of an
array as in

x <- range(array_y)

which gives me two values such as

[1] -2 9

I need to be able to test if this range of values includes a third value.  For
example I'd like to query

1) does the range of -2 to 9 include 3, answer TRUE
2) does the range of -2 to 9 include -6, answer FALSE?

All values could be negative or positive.  Is there a R function that will test
this or do I need to programme it?  I have searched but not found one.

Thanks

J

==============================Dr. Jim Maas
University of East Anglia

	[[alternative HTML version deleted]]

On 2011-02-17 07:36, Maas James Dr (MED) wrote:
>
> I'm using the range command to get the minimum and maximum values of an
array as in
>
> x<- range(array_y)
>
> which gives me two values such as
>
> [1] -2 9
>
> I need to be able to test if this range of values includes a third value. 
For example I'd like to query
>
> 1) does the range of -2 to 9 include 3, answer TRUE
> 2) does the range of -2 to 9 include -6, answer FALSE?
>
> All values could be negative or positive.  Is there a R function that will
test this or do I need to programme it?  I have searched but not found one.
Here too you can use findInterval():

   findInterval( -2, range(array_y) ) == 1

You may want to set the 'rightmost.closed' argument to TRUE.

Peter Ehlers
>
> Thanks
>
> J
>
> ==============================> Dr. Jim Maas
> University of East Anglia
>
> 	[[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.

On Feb 17, 2011, at 10:36 AM, Maas James Dr (MED) wrote:
>
> I'm using the range command to get the minimum and maximum values of  
> an array as in
>
> x <- range(array_y)
>
> which gives me two values such as
>
> [1] -2 9
>
> I need to be able to test if this range of values includes a third  
> value.  For example I'd like to query
>
> 1) does the range of -2 to 9 include 3, answer TRUE
> 2) does the range of -2 to 9 include -6, answer FALSE?
>
> All values could be negative or positive.  Is there a R function  
> that will test this or do I need to programme it?  I have searched  
> but not found one.
There is a function that handles intervals well, findInterval:

 > findInterval(0, c(-2, 9))
[1] 1
 > findInterval(-3, c(-2, 9))
[1] 0
 > findInterval(10, c(-2, 9))
[1] 2

So:

isxInRange_y <- function(x, y) findInterval(x, range(y)) == 1

If you want to omit NA's which would otherwise poison the effort, you  
need to wrap the y argument in na.omit().

-- 
David.
>
> Thanks
>
> J
>
> ==============================> Dr. Jim Maas
> University of East Anglia
>
> 	[[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.
David Winsemius, MD
West Hartford, CT