done at infinite precision, then x==0
may not work.
-thomas
--- On Thu, 14/8/08, Roland Rau [EMAIL PROTECTED] wrote:
From: Roland Rau [EMAIL PROTECTED]
Subject: Re: [R] ignoring zeros or converting to NA
To: rcoder [EMAIL PROTECTED]
Cc: r-help@r-project.org
Received: Thursday, 14
Hi: If I remember correctly, I think I gave you something like mat[mat
== 0]-NA. I think what you're doing below is pretty different from
that but I may not be understanding what you want ? Let me know if I can
clarify more because my intention was not to guide you
into doing below. Looping is
Sorry for jumping in. I haven't read the entire conversation. But imagine you
want to compute 1/x for the entire matrix and your matrix has 0s and NAs.
Then you could do:
##define function
f-function(x){1/x}
##sample data
y=c(0,1,2,3,4,5,6,7,NA)
##arrange in matrix
mat=matrix(y,3,3)
: Thursday, August 14, 2008 1:46 PM
To: r-help@r-project.org
Subject: Re: [R] ignoring zeros or converting to NA
Sorry for jumping in. I haven't read the entire conversation. But imagine
you
want to compute 1/x for the entire matrix and your matrix has 0s and NAs.
Then you could do:
##define
Hi,
since many suggestions are following the form of
x[x==0] (or similar)
I would like to ask if this is really recommended?
What I have learned (the hard way) is that one should not test for
equality of floating point numbers (which is the default for R's numeric
values, right?) since the
Integers (up to a fairly high limit) are represented exactly, as are fractions
whose denominator is a power of two (again up to a fairly high limit), so x==0
is fine in that sense.
If x is computed by floating point operations you do have to worry whether
these are exact, eg, with
The help page on binary operators (see ?==) confirms that binary
representation of fractional representation is not catered for and
points to all.equal as a more suitable test method for those cases.
Steve E
Thomas Lumley [EMAIL PROTECTED] 13/08/2008 16:47
Integers (up to a fairly high limit)
FYI,
there is an isZero() in the R.utils package that allows you to specify
the precision. It looks like this:
isZero - function (x, neps=1, eps=.Machine$double.eps, ...) {
(abs(x) neps*eps);
}
/Henrik
On Wed, Aug 13, 2008 at 8:23 AM, Roland Rau [EMAIL PROTECTED] wrote:
Hi,
since many
Thank you for all your replies.
Borrowing an alternative solution kindly provided by Mark Leeds, I am using
a conditional statement to pass non-zero values to a holding matrix that has
cells initially set to NA. The code is as follows:
##Code Start
mat_zeroless-matrix(NA,5000,2000)
] ignoring zeros or converting to NA
To: rcoder [EMAIL PROTECTED]
Cc: r-help@r-project.org
Received: Thursday, 14 August, 2008, 1:23 AM
Hi,
since many suggestions are following the form of
x[x==0] (or similar)
I would like to ask if this is really recommended?
What I have learned (the hard
Hi everyone,
I have a matrix that has a combination of zeros and NAs. When I perform
certain calculations on the matrix, the zeros generate Inf values. Is
there a way to either convert the zeros in the matrix to NAs, or only
perform the calculations if not zero (i.e. like using something similar
when you read it in na.string=0
On Tue, Aug 12, 2008 at 1:43 PM, rcoder [EMAIL PROTECTED] wrote:
Hi everyone,
I have a matrix that has a combination of zeros and NAs. When I perform
certain calculations on the matrix, the zeros generate Inf values. Is
there a way to either convert the zeros
rcoder [EMAIL PROTECTED] wrote:
I have a matrix that has a combination of zeros and NAs. When I perform
certain calculations on the matrix, the zeros generate Inf values. Is
there a way to either convert the zeros in the matrix to NAs, or only
perform the calculations if not zero (i.e. like
On Tue, 12 Aug 2008, Mike Prager wrote:
rcoder [EMAIL PROTECTED] wrote:
I have a matrix that has a combination of zeros and NAs. When I perform
certain calculations on the matrix, the zeros generate Inf values. Is
there a way to either convert the zeros in the matrix to NAs, or only
perform
I have been reading this thread and I am having a hard interpreting
what these mean. I know that the result is that all of the values
that are zero in a are replaced by NA. Let me try and write it out
is.na(a[a==0] ) - TRUE
you pull out of a all of the times that are equal to zero then is.na
zeros or converting to NA
I have been reading this thread and I am having a hard interpreting
what these mean. I know that the result is that all of the values
that are zero in a are replaced by NA. Let me try and write it out
is.na(a[a==0] ) - TRUE
you pull out of a all of the times
On Tue, 12 Aug 2008, stephen sefick wrote:
I have been reading this thread and I am having a hard interpreting
what these mean. I know that the result is that all of the values
that are zero in a are replaced by NA. Let me try and write it out
is.na(a[a==0] ) - TRUE
you pull out of a all of
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