> -Original Message-
> From: r-devel-boun...@r-project.org
> [mailto:r-devel-boun...@r-project.org] On Behalf Of Duncan Murdoch
> Sent: Tuesday, March 17, 2009 12:15 PM
> To: Daniel Murphy
> Cc: r-devel@r-project.org
> Subject: Re: [Rd] Match .3 in a sequence
>
On 3/17/2009 11:26 AM, Daniel Murphy wrote:
Is this a reasonably fast way to do an approximate match of a vector x to
values in a list?
match.approx <- function(x,list,tol=.0001)
sapply(apply(abs(outer(list,x,"-"))
If you are willing to assume that the list values are all multiples of
2*t
Is this a reasonably fast way to do an approximate match of a vector x to
values in a list?
match.approx <- function(x,list,tol=.0001)
sapply(apply(abs(outer(list,x,"-"))wrote:
> Well, first of all, seq(from=.2,to=.3) gives c(0.2), so I assume you
> really mean something like seq(from=.2,to=
On Tue, Mar 17, 2009 at 10:04:39AM -0400, Stavros Macrakis wrote:
...
> 1) Factor allows repeated levels, e.g. factor(c(1),c(1,1,1)), with no
> warning or error.
Yes, this is a confusing behavior, since repeated levels are never meaningful.
> 2) Even from distinct inputs, factor of a numeric vect
Petr,
Thank you for the detailed diagnosis of the bizarre behavior I
reported, which seems to indicate several distinct problems in the
underlying code:
1) Factor allows repeated levels, e.g. factor(c(1),c(1,1,1)), with no
warning or error.
2) Even from distinct inputs, factor of a numeric vecto
Wacek Kusnierczyk wrote:
>
>
> there's one more curiosity about factors, in particular, ordered factors:
>
> ord <- as.ordered(nums); ord
> # [1] 0.300 0.3 0.3
> 0.300
> # Levels: 0.300 < 0.3 < 0.3 < 0.300
>
>
On Tue, Mar 17, 2009 at 10:15:39AM +0100, Wacek Kusnierczyk wrote:
...
> there's one more curiosity about factors, in particular, ordered factors:
>
> ord <- as.ordered(nums); ord
> # [1] 0.300 0.3 0.3
> 0.300
> # Levels: 0.30
Petr Savicky wrote:
> On Mon, Mar 16, 2009 at 07:39:23PM -0400, Stavros Macrakis wrote:
> ...
>
>> Let's look at the extraordinarily poor behavior I was mentioning. Consider:
>>
>> nums <- (.3 + 2e-16 * c(-2,-1,1,2)); nums
>> [1] 0.3 0.3 0.3 0.3
>>
>> Though they all print as .3 with the default
On Mon, Mar 16, 2009 at 07:39:23PM -0400, Stavros Macrakis wrote:
...
> Let's look at the extraordinarily poor behavior I was mentioning. Consider:
>
> nums <- (.3 + 2e-16 * c(-2,-1,1,2)); nums
> [1] 0.3 0.3 0.3 0.3
>
> Though they all print as .3 with the default precision (which is
> normal and
Got it. Thank you all.
On Mon, Mar 16, 2009 at 4:39 PM, Stavros Macrakis wrote:
> The factor approach is horrifically ugly and dangerous.
>
> Even if it didn't have the extraordinarily poor behavior documented
> below, it simply isn't well-defined what it should do. The explicit
> approximation
The factor approach is horrifically ugly and dangerous.
Even if it didn't have the extraordinarily poor behavior documented
below, it simply isn't well-defined what it should do. The explicit
approximation route is far far preferable in every way: more
predictable, more controllable, and even (th
I have a matrix whose columns were filled with values which were functions
of cvseq<-seq(.2,.3,by=.1) (and a row value of mode integer). To do a lookup
for cv=.3 later, I wanted to match(.3,cvseq), which gave me NA, hence my
question. I thought R would match .3 in cvseq within .Machine$double.eps,
Petr Savicky wrote:
> On Mon, Mar 16, 2009 at 06:36:53AM -0700, Daniel Murphy wrote:
>
>> Hello:I am trying to match the value 0.3 in the sequence seq(.2,.3). I get
>>
>>> 0.3 %in% seq(from=.2,to=.3)
>>>
>> [1] FALSE
>>
>
> As others already pointed out, you should use seq(from=
On Mon, Mar 16, 2009 at 06:36:53AM -0700, Daniel Murphy wrote:
> Hello:I am trying to match the value 0.3 in the sequence seq(.2,.3). I get
> > 0.3 %in% seq(from=.2,to=.3)
> [1] FALSE
As others already pointed out, you should use seq(from=0.2,to=0.3,by=0.1)
to get 0.3 in the sequence. In order to
Well, first of all, seq(from=.2,to=.3) gives c(0.2), so I assume you
really mean something like seq(from=.2,to=.3,by=.1), which gives
c(0.2, 0.3).
%in% tests for exact equality, which is almost never a good idea with
floating-point numbers.
You need to define what exactly you mean by "in" for flo
Duncan Murdoch wrote:
> On 3/16/2009 9:36 AM, Daniel Murphy wrote:
>> Hello:I am trying to match the value 0.3 in the sequence seq(.2,.3).
>> I get
>>> 0.3 %in% seq(from=.2,to=.3)
>> [1] FALSE
>> Yet
>>> 0.3 %in% c(.2,.3)
>> [1] TRUE
>> For arbitrary sequences, this "invisible .3" has been problema
On 3/16/2009 9:36 AM, Daniel Murphy wrote:
Hello:I am trying to match the value 0.3 in the sequence seq(.2,.3). I get
0.3 %in% seq(from=.2,to=.3)
[1] FALSE
Yet
0.3 %in% c(.2,.3)
[1] TRUE
For arbitrary sequences, this "invisible .3" has been problematic. What is
the best way to work around thi
Hello:I am trying to match the value 0.3 in the sequence seq(.2,.3). I get
> 0.3 %in% seq(from=.2,to=.3)
[1] FALSE
Yet
> 0.3 %in% c(.2,.3)
[1] TRUE
For arbitrary sequences, this "invisible .3" has been problematic. What is
the best way to work around this?
Thank you.
Dan
[[alternative HTML
18 matches
Mail list logo
