[R] Check if a character vector can be coerced to numeric?

2013-03-21 Thread Jonathan Greenberg
Given an arbitrary set of character vectors:

myvect1 - c(abc,3,4)
myvect2 - c(2,3,4)

I would like to develop a function that will convert any vectors that can
be PROPERLY converted to a numeric (myvect2) into a numeric, but leaves
character vectors which cannot be converted (myvect1) alone.  Is there any
simple way to do this (e.g. some function that tests if a vector is
coercible to a numeric before doing so)?

--j

-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
607 South Mathews Avenue, MC 150
Urbana, IL 61801
Phone: 217-300-1924
http://www.geog.illinois.edu/~jgrn/
AIM: jgrn307, MSN: jgrn...@hotmail.com, Gchat: jgrn307, Skype: jgrn3007

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Re: [R] Check if a character vector can be coerced to numeric?

2013-03-21 Thread Prof Brian Ripley

On 21/03/2013 18:20, Jonathan Greenberg wrote:

Given an arbitrary set of character vectors:

myvect1 - c(abc,3,4)
myvect2 - c(2,3,4)

I would like to develop a function that will convert any vectors that can
be PROPERLY converted to a numeric (myvect2) into a numeric, but leaves
character vectors which cannot be converted (myvect1) alone.  Is there any
simple way to do this (e.g. some function that tests if a vector is
coercible to a numeric before doing so)?

--j


?type.convert

It does depend what you mean by 'properly'.  Can 
123.456789012344567890123455 be converted 'properly'?  [See the NEWS 
for R-devel.]


--
Brian D. Ripley,  rip...@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel:  +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UKFax:  +44 1865 272595

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Re: [R] Check if a character vector can be coerced to numeric?

2013-03-21 Thread Jeff Newmiller
Using capital letters does not improve clarity... it just offends people.

Does read.table and friends not do this to your satisfaction already with 
as.is=TRUE? If not, shouldn't coercing it and checking for NA serve?

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Jonathan Greenberg j...@illinois.edu wrote:

Given an arbitrary set of character vectors:

myvect1 - c(abc,3,4)
myvect2 - c(2,3,4)

I would like to develop a function that will convert any vectors that
can
be PROPERLY converted to a numeric (myvect2) into a numeric, but leaves
character vectors which cannot be converted (myvect1) alone.  Is there
any
simple way to do this (e.g. some function that tests if a vector is
coercible to a numeric before doing so)?

--j

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R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] Check if a character vector can be coerced to numeric?

2013-03-21 Thread Jonathan Greenberg
Yep, type.convert was exactly what I was looking for (with as.is=TRUE).
 Thanks!


On Thu, Mar 21, 2013 at 1:31 PM, Prof Brian Ripley rip...@stats.ox.ac.ukwrote:

 On 21/03/2013 18:20, Jonathan Greenberg wrote:

 Given an arbitrary set of character vectors:

 myvect1 - c(abc,3,4)
 myvect2 - c(2,3,4)

 I would like to develop a function that will convert any vectors that can
 be PROPERLY converted to a numeric (myvect2) into a numeric, but leaves
 character vectors which cannot be converted (myvect1) alone.  Is there any
 simple way to do this (e.g. some function that tests if a vector is
 coercible to a numeric before doing so)?

 --j


 ?type.convert

 It does depend what you mean by 'properly'.  Can
 123.456789012344567890123455 be converted 'properly'?  [See the NEWS for
 R-devel.]

 --
 Brian D. Ripley,  rip...@stats.ox.ac.uk
 Professor of Applied Statistics,  
 http://www.stats.ox.ac.uk/~**ripley/http://www.stats.ox.ac.uk/~ripley/
 University of Oxford, Tel:  +44 1865 272861 (self)
 1 South Parks Road, +44 1865 272866 (PA)
 Oxford OX1 3TG, UKFax:  +44 1865 272595

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-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
607 South Mathews Avenue, MC 150
Urbana, IL 61801
Phone: 217-300-1924
http://www.geog.illinois.edu/~jgrn/
AIM: jgrn307, MSN: jgrn...@hotmail.com, Gchat: jgrn307, Skype: jgrn3007

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and provide commented, minimal, self-contained, reproducible code.