[R] Aggregating the matrices

[Sergey Goriatchev]

Gabor, David, thank you.

David, your last suggestion is what I need.

Regards,
Sergey

On Mon, Sep 6, 2010 at 16:12, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Sep 6, 2010, at 9:56 AM, Sergey Goriatchev wrote:
>
>> Hello everyone.
>>
>> Say we have the following:
>>
>> a <- matrix(c(-75, 3, 5, 9, 2, 3, 5), nrow=1, dim=list("06092010",
>> c("ES", "PT", "Z ", "CF", "GX", "ST", "EO")))
>> b <- matrix(c(-5, 2, 4, 12, 5), nrow=1, dim=list("06092010", c("PT",
>> "CF", "AT", "EM", "ST")))
>> d <- cbind(a, b)
>>
>> I want to calculate sums of the columns that have similar column names
>> and then output this summary
>> What I want to have is an array that looks like:
>>
>> ES  PT Z  CF...
>> -75  -2  5  11...
>>
>> I tried the following, but it did not work:
>> aggregate(d, list(colnames(d)), sum)
>
> ES is not in the duplicated column names so perhaps your English
> specification is not what you meant:
>> d
>          ES PT Z  CF GX ST EO PT CF AT EM ST
> 06092010 -75  3  5  9  2  3  5 -5  2  4 12  5
>
>> dupled <- colnames(d)[duplicated(colnames(d))]
>> sapply(dupled, function(x) sum( d[, x]))
> PT CF ST
>  3  9  3
>
> If you wanted simple a sum over unique column names then it would have been
> somewhat simpler (no need to construct a duplicated set):
>
>> sapply(unique(colnames(d)), function(x) sum( d[, x]))
>  ES  PT  Z   CF  GX  ST  EO  AT  EM
> -75   3   5   9   2   3   5   4  12
>
>>
>> How can I achieve my objective?
>>
>> Thank you in advance.
>>
>> Sergey
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>
> David Winsemius, MD
> West Hartford, CT
>
>



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