R help - Nov 2015 - Subsetting dataframe by the nearest values of a vector elements

Hello,
I have a dataset with two columns 1. cross_section (range: 0~635), and 
2. elevation. The dataset has more than 100 rows. Now I want to make a 
subset on the condition that the 'cross_section' column will pick up the
nearest cell from another vector (say 0, 50,100,150,200,.....,650).
How can I do this? I would really appreciate a solution.
Regards,
Harun
-- 

<mailto:mhrashidbau at yahoo.com>
<mailto:mhrashidbau at yahoo.com>

	[[alternative HTML version deleted]]

Harun,

Can you give a simple example?

If your cross_section looked like this
c(144, 179, 214, 39, 284, 109, 74, 4, 249)
and your other vector looked like this
c(0, 50, 100, 150, 200, 250, 300, 350)
what would you want your subset to look like?

Jean

On Mon, Nov 9, 2015 at 7:26 AM, Harun Rashid via R-help <
r-help at r-project.org> wrote:
> Hello,
> I have a dataset with two columns 1. cross_section (range: 0~635), and
> 2. elevation. The dataset has more than 100 rows. Now I want to make a
> subset on the condition that the 'cross_section' column will pick
up the
> nearest cell from another vector (say 0, 50,100,150,200,.....,650).
> How can I do this? I would really appreciate a solution.
> Regards,
> Harun
> --
>
> <mailto:mhrashidbau at yahoo.com>
> <mailto:mhrashidbau at yahoo.com>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
	[[alternative HTML version deleted]]

Do you want the "closest" or what range it is in?  If you want the
range,
then use 'cut':
> x <- c(144, 179, 214, 39, 284, 109, 74, 4, 249)
> range <- c(0, 50, 100, 150, 200, 250, 300, 350)
> result <- cut(x, breaks = range)
> cbind(x, as.character(result))
      x
 [1,] "144" "(100,150]"
 [2,] "179" "(150,200]"
 [3,] "214" "(200,250]"
 [4,] "39"  "(0,50]"
 [5,] "284" "(250,300]"
 [6,] "109" "(100,150]"
 [7,] "74"  "(50,100]"
 [8,] "4"   "(0,50]"
 [9,] "249" "(200,250]"



Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

On Mon, Nov 9, 2015 at 12:19 PM, Adams, Jean <jvadams at usgs.gov> wrote:
> Harun,
>
> Can you give a simple example?
>
> If your cross_section looked like this
> c(144, 179, 214, 39, 284, 109, 74, 4, 249)
> and your other vector looked like this
> c(0, 50, 100, 150, 200, 250, 300, 350)
> what would you want your subset to look like?
>
> Jean
>
> On Mon, Nov 9, 2015 at 7:26 AM, Harun Rashid via R-help <
> r-help at r-project.org> wrote:
>
> > Hello,
> > I have a dataset with two columns 1. cross_section (range: 0~635), and
> > 2. elevation. The dataset has more than 100 rows. Now I want to make a
> > subset on the condition that the 'cross_section' column will
pick up the
> > nearest cell from another vector (say 0, 50,100,150,200,.....,650).
> > How can I do this? I would really appreciate a solution.
> > Regards,
> > Harun
> > --
> >
> > <mailto:mhrashidbau at yahoo.com>
> > <mailto:mhrashidbau at yahoo.com>
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > 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.
> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>
	[[alternative HTML version deleted]]

> On Nov 9, 2015, at 9:19 AM, Adams, Jean <jvadams at usgs.gov> wrote:
> 
> Harun,
> 
> Can you give a simple example?
> 
> If your cross_section looked like this
> c(144, 179, 214, 39, 284, 109, 74, 4, 249)
> and your other vector looked like this
> c(0, 50, 100, 150, 200, 250, 300, 350)
> what would you want your subset to look like?
> 
> Jean
> 
> On Mon, Nov 9, 2015 at 7:26 AM, Harun Rashid via R-help <
> r-help at r-project.org> wrote:
> 
>> Hello,
>> I have a dataset with two columns 1. cross_section (range: 0~635), and
>> 2. elevation. The dataset has more than 100 rows. Now I want to make a
>> subset on the condition that the 'cross_section' column will
pick up the
>> nearest cell from another vector (say 0, 50,100,150,200,.....,650).
>> How can I do this? I would really appreciate a solution.
If you what the "other vector" to define the ?cell? boundaries, and
using Jean?s example, it is a simple application of `findInterval`:
> inp <- c(144, 179, 214, 39, 284, 109, 74, 4, 249)
> mids <- c(0, 50, 100, 150, 200, 250, 300, 350)
> findInterval( inp, c(mids) )
[1] 3 4 5 1 6 3 2 1 5

On the other hand ...

To find the number of "closest point", this might help:

> findInterval(inp, c( mids[1]-.001, head(mids,-1)+diff(mids)/2,
tail(mids,1)+.001 ) )
[1] 4 5 5 2 7 3 2 1 6



? 
David Winsemius
Alameda, CA, USA