The objects are
> centroid
x y
669.5 313.5
> str(centroid)
Named num [1:2] 670 314
- attr(*, "names")= chr [1:2] "x" "y"
or
> centroid
x y
[1,] 659.5 472.5
[2,] 659.5 473.5
> str(centroid)
num [1:2, 1:2] 660 660 472 474
- attr(*, "dimnames")=List of 2
..$ : NULL
..$ : chr [1:2] "x" "y"
I hope this help to clarify the objects I'm getting with the loop.
2009/8/3 David Winsemius <dwinsem...@comcast.net>
> So you need to show us how you made the second object. (The Posting Guide's
> phrase "reproducible code" is hereby invoked.)
>
> On Aug 3, 2009, at 10:18 AM, Paulo Eduardo Cardoso wrote:
>
> Both objects are numeric, but they differ in structure and I don't know how
> to handle both with a single function to get means.
> When I try to apply colMeans to a named numeric object like this:
>
> Named num [1:2] 670 314
> - attr(*, "names")= chr [1:2] "x" "y"
>
> I get the error messages:
>
> Error in colMeans(centroid) :
> 'x' must be an array of at least two dimensions
>
> and apply(object,2,mean)
>
> Error in apply(object, 2, mean) : dim(X) must have a positive length
>
> There are something very basic that I'm missing.
>
> 2009/8/3 David Winsemius <dwinsem...@comcast.net>
>
>>
>> On Aug 3, 2009, at 9:52 AM, Paulo Eduardo Cardoso wrote:
>>
>> Thanks. Works
>> A doubt.
>>
>> I asked that because I have a loop that can generate objects like that or
>> this one
>>
>>
>> str(object)
>> Named num [1:2] 670 314
>> - attr(*, "names")= chr [1:2] "x" "y"
>>
>> To avoid using a ifelse() to calculate means of x and y, I'd like a
>> function that handle with this named numeric object and that list. Any
>> chance of do it with a single function?
>>
>>
>> I do not see any list object. Lists and arrays (of which the two
>> dimensional ones are of type "matrix") are quite different basic data
>> structures in R. If you interchange the use of those terms you will not get
>> useful replies from R users. Those two object both appear to be matrices and
>> both should be handled by those functions.
>>
>>
>> 2009/8/3 David Winsemius <dwinsem...@comcast.net>
>>
>>>
>>> On Aug 3, 2009, at 9:07 AM, Paulo Eduardo Cardoso wrote:
>>>
>>> Maybe a very basic question.
>>>> How can I get mean of a object like this
>>>>
>>>> str(object)
>>>>>
>>>> num [1:53, 1:2] 734 734 736 734 736 ...
>>>> - attr(*, "dimnames")=List of 2
>>>> ..$ : NULL
>>>> ..$ : chr [1:2] "x" "y"
>>>>
>>>> I want the mean of both x and y
>>>>
>>>
>>> apply(object, 2, mean)
>>>
>>> or...
>>>
>>> colMeans(object) # which will be faster
>>>
>>>
>>>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>
--
_______________
Paulo E. Cardoso
[[alternative HTML version deleted]]
______________________________________________
R-help@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.
