Definitely out of sequence - it should be
[,1] [,2]
[1,] 4 21
[2,] 5 22
[3,] 6 23
[4,] 7 24
[5,] 8 25
[6,] 9 26
[7,] 10 27
[8,] 11 28
[9,] 12 29
[10,] 13 30
[11,] 14 31
On 16 November 2010 20:12, David Winsemius <dwinsem...@comcast.net> wrote:
>
> On Nov 16, 2010, at 2:33 PM, Paolo Rossi wrote:
>
> Hi,
>> Can anyone suggest a clever way to compute a rolling weekly average of
>> the
>> columns in a matrix? The column bit is straightforward use apply given
>> a
>> function which does what you want on a column. With regard to a particular
>> column, the obvious way is to run a for loop indexing the last 7 days and
>> computing the average . I simply would like to know if there is a better
>> /
>> quicker way.
>>
>
> There is a rollmean function in package zoo. See below.
>
>
>
>>
>>
>> Code:
>> Given a,
>>
>>> a= array(1:100, dim = c(17,2))
>>> a
>>>
>> [,1] [,2]
>> [1,] 1 18
>> [2,] 2 19
>> [3,] 3 20
>> [4,] 4 21
>> [5,] 5 22
>> [6,] 6 23
>> [7,] 7 24
>> [8,] 8 25
>> [9,] 9 26
>> [10,] 10 27
>> [11,] 11 28
>> [12,] 12 29
>> [13,] 13 30
>> [14,] 14 31
>> [15,] 15 32
>> [16,] 16 33
>> [17,] 17 34
>> one needs to start computing the average from obs 7 s (at obs 7 you have a
>> full week to compute the average) and compute the rolling weekly average
>> from day 7 onwards
>> Results will look like b
>> [,1] [,2]
>> [1,] 4 14
>> [2,] 5 21
>>
>
> I think you got your first ones out of sequence:
>
> > apply(a, 2, rollmean, k=7)
> [,1] [,2]
> [1,] 4 21
> [2,] 5 22
> [3,] 6 23
> [4,] 7 24
> [5,] 8 25
> [6,] 9 26
> [7,] 10 27
> [8,] 11 28
> [9,] 12 29
> [10,] 13 30
> [11,] 14 31
>
>
> --
> David.
>
>> [3,] 6 22
>> [4,] 7 23
>> [5,] 8 24
>> [6,] 9 25
>> [7,] 10 26
>> [8,] 11 27
>> [9,] 12 28
>> [10,] 13 29
>> Thanks in advance,
>>
>> Paolo
>>
>>
>>
>> On 15 November 2010 20:59, wangwallace <talentt...@gmail.com> wrote:
>>
>>
>>> Hey,
>>>
>>> I am hoping someone can help me with a sampling question.
>>>
>>> I have a data frame of 8 variables (the first column is the subjects'
>>> id):
>>>
>>> SubID CSE1 CSE2 CSE3 CSE4 WSE1 WSE2 WSE3 WSE4
>>> 1 6 5 6 2 6 2 2 4
>>> 2 6 4 7 2 6 6 2 3
>>> 3 5 5 5 5 5 5 4 5
>>> 4 5 4 3 4 4 4 5 2
>>> 5 5 6 7 5 6 4 4 1
>>> 6 5 4 3 6 4 3 7 3
>>> 7 3 6 6 3 6 5 2 1
>>> 8 3 6 6 3 6 5 4 7
>>>
>>> the 6 variables are categorized into two groups with CSE1, CSE2, CSE3,
>>> and
>>> CSE4 in one group and the rest in another group.
>>>
>>> sample(data[,2:4],2,replace=FALSE)
>>>>
>>>
>>> CSE1 CSE2
>>> 1 6 5
>>> 2 6 4
>>> 3 5 5
>>> 4 5 4
>>> 5 5 6
>>> 6 5 4
>>> 7 3 6
>>> 8 3 6
>>>
>>> Now I want to sample 1 column from another group of variables (i.e.,
>>> WSE1,
>>> WSE2, WSE3, WSE4), but I want to restrict a vector I am going to sample
>>> from
>>> to only those columns that are not correspond to GROUP 1 variables I have
>>> sampled. That is, I want to sample a column from WSE3, WSE4 Columns
>>> corresponding to CSE1 and CSE2 (i.e., WSE1, WSE2) need to be dropped.
>>>
>>> How can I do this? what if I want to repeat this whole process (drawing 2
>>> random columns from CSE1, CSE2, CSE3, and CSE4 first, AND then another
>>> random column from WSE1, WSE2, WSE3, and WSE4) for 1000 times. any ideas?
>>>
>>> Many thanks in advance!!
>>>
>>> --
>>> View this message in context:
>>> http://r.789695.n4.nabble.com/Sampling-problem-tp3043804p3043804.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
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>>> <http://www.r-project.org/posting-guide.html>
>>>
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>> [[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<http://www.r-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> David Winsemius, MD
> West Hartford, CT
>
>
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