[R] splitting data

[Bert Gunter]

?tapply

e.g.

with(yourdata, tapply(A,list(year,month),sum,simplify=FALSE))

This assumes "sum them up" means summing each column separately. You
were unclear as to exactly what you meant by this.

-- Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
Clifford Stoll




On Mon, Sep 8, 2014 at 12:08 PM, eliza botto <eliza_botto at hotmail.com> wrote:
> Dear R members,
>
> I have this data frame of 100 years in the following format
>
> year            month       day         A           B           C         D
>
> where  A,B,C and D are item number sold each day. I am trying
>
> 1-split the data w.r.t the monthly values for each year
>
> 2-then, sum them up
>
> I am pasting here just a part of data to make it more clearer
>
> structure(list(year = c(1961, 1961, 1961, 1961, 1961, 1961, 1961,
> 1961, 1961, 1961, 1961, 1961), month = c(1, 1, 1, 1, 1, 1, 1,
> 1, 1, 1, 1, 1), day = 1:12, A = 1:12, B = 3:14, C = 6:17, D = 16:27), .Names = c("year",
> "month", "day", "A", "B", "C", "D"), row.names = c(NA, 12L), class = "data.frame")
>
> I initially tried to use "dcast" command but for no use.
>
> Your kind help is needed.
>
> Thanks in advance
>
> Eliza
>
>
>
>         [[alternative HTML version deleted]]
>
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