[R] Creating a matrix
jholtman at gmail.com
Thu Oct 9 04:15:55 CEST 2008
You can read it in as a data.frame and then use 'aggregate' to get the mean:
> x <- read.table(textConnection(' Seller Art. Unit_Price
+ 1 v1 p1 9.148352
+ 2 v1 p1 2.858073
+ 3 v1 p2 3.775315
+ 4 v1 p2 9.821429
+ 5 v1 p3 3.286827
+ 6 v1 p3 11.105769') , header=TRUE)
Seller Art. Unit_Price
1 v1 p1 9.148352
2 v1 p1 2.858073
3 v1 p2 3.775315
4 v1 p2 9.821429
5 v1 p3 3.286827
6 v1 p3 11.105769
> aggregate(x$Unit_Price, list(x$Seller, x$Art.), mean)
Group.1 Group.2 x
1 v1 p1 6.003213
2 v1 p2 6.798372
3 v1 p3 7.196298
On Wed, Oct 8, 2008 at 4:03 PM, SP&BM <sandra_peneda at hotmail.com> wrote:
> Good evening.
> I have this following table and I would like to turn it into a matrix in
> which my rows would be filled with de "Sellers", my columns with my
> "Articles" and my data would be the mean unitary price used by each seller
> in each produt.
> Seller Art. Unit Price
> 1 v1 p1 9.148352
> 2 v2 p1 2.858073
> 3 v3 p1 3.775315
> 4 v4 p1 9.821429
> 5 v3 p1 3.286827
> 6 v5 p2 11.105769
> This is only the head of a table with more than 400.000 lines, 6.000 sellers
> and 4500 produts.
> Can anybody help me in suh a task considered very difficult by someone that
> has heard about R only a few hours?
> Thank you!
> View this message in context: http://www.nabble.com/Creating-a-matrix-tp19886510p19886510.html
> Sent from the R help mailing list archive at Nabble.com.
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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