Yes,

df is your data.frame.

tapply(df$y, df$x, sum)


On 14/02/07, d. sarthi maheshwari <samay.sar@gmail.com> wrote:
>
> Hi
>
> Sorry if this is a wrong post in the forum. Please suggest if this is a
> correct forum to discuss R related basic problem.
>
> I wanted to perform the following task by using R:
>
> e.g.
> input data.frame
> x                  y
> ============
> a                10
> b                20
> a                10
> a                10
> b                15
> b                15
> b                20
>
> In o/p i need
>
> x            y
> =========
> a           30
> b           70
>
> Currently i am storing the data.frame as a database table by using
> sqlSave.
> Then I am retrieving the data using sqlQuery command. In the query I am
> using Group by function of SQL.
>
> is there any smarter way to this in R?
>
>
> --
> thanks
> Sar
>
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>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná
Brasil

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