[R] Between the values

[Dan Davison]

Shubha Vishwanath Karanth wrote:
> 
> Or at least anyways of defining a vector/(or something like that) which
> has all values between 0 and 1? 
> 
> For example:
> C(0,1) is incorrect, seq(0,1,0.2) is also incorrect, seq(0,1,0.00001) is
> also incorrect.... How does one specify this?
> 
> 

Hi Shubha,

What are you trying to do? The set of all real numbers between 0 and 1 is
infinitely large. Obviously you can't explicitly construct an infinitely
large vector in R. If you want to construct an implicit specification of
that set, then I think I've already given you a good answer in R: define a
predicate function and use it. E.g.

between <- function(x, low, high) x > low && x < high

I don't know much at all about symbolic mathematics packages like Maple and
Mathematica, but maybe you're thinking of something you can do in those
softwares? R is not trying to be a competitor to them; they do lots of
things R doesn't, and vice versa.

Dan


Shubha Vishwanath Karanth wrote:
> 
> 
> Thanks, Shubha
>  
> 
> -----Original Message-----
> From: Dan Davison [mailto:davison at stats.ox.ac.uk] 
> Sent: Tuesday, August 12, 2008 5:54 PM
> To: Shubha Vishwanath Karanth
> Cc: r-help at stat.math.ethz.ch
> Subject: Re: [R] Between the values
> 
> On Tue, Aug 12, 2008 at 05:16:01PM +0530, Shubha Vishwanath Karanth
> wrote:
>> Hi R,
>> 
>>  
>> 
>> This is a very trivial one....
>> 
>>  
>> 
>> C=0.1
>> 
>>  
>> 
>> I want to check whether my value of C is between 0 and 1
> exclusively....
>> I don't want to use (C>0 & C<1). And I can't use a single statement
> like
>> (0<C<1). Is there a between function? Or how do we specify from 0 to
> 1?
>> Does %in% help me?
> 
> If you don't like (C > 0 && C < 1), then just write your own function
> is.between(x, low, high) (NB1 you've basically written it already; NB2
> single '&' for the vectorised version 'are.between'). People's
> personal tastes about what's desirable will vary, and anyway it's good
> practice to build up your own personal library of
> functions. Ultimately if you have a high quality collection of related
> functions for working on a particular sort of problem, then you should
> publish them as an R package on CRAN.
> 
> Dan
> 
>> 
>>  
>> 
>>  
>> 
>> Many Thanks,
>> 
>> Shubha
>> 
>>  
>> 
>> This e-mail may contain confidential and/or privileged
> i...{{dropped:13}}
>> 
>> ______________________________________________
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>> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> -- 
> www.stats.ox.ac.uk/~davison
> This e-mail may contain confidential and/or privileged i...{{dropped:10}}
> 
> ______________________________________________
> 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.
> 
> 

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