[R] urgent: question concerning data manipulation

[MacQueen, Don]

Here is one way. There will be many ways to do it; I offer this one
because it is very general.

-Don


tmp <- split(testdata, testdata$personId)

myfun <- function(df) {
  dfo <- df
  if (any(df$law=='SVG')) dfo$svg <- 1 else dfo$svg <- 0
  dfo
}

tmpo <- lapply(tmp,myfun)

testout <- do.call('rbind', tmpo)

> print(testout)
     personId  law article svg
1.1         1  SVG      10   1
1.2         1  SVG      10   1
2.3         2 StGB     123   1
2.4         2 StGB     122   1
2.5         2  SVG      10   1
2.6         2  AuG      40   1
2.7         2 StGB     126   1
3           3  SVG      10   1
4.9         4 StGB     111   0
4.10        4  AuG      40   0






-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 3/4/13 7:44 AM, "David Studer" <studerov at gmail.com> wrote:

Hello everyone!

Does anyone of you know how I could solve the following problem.
I guess, it is not a very difficult question, but I simply lack of the
right idea:

I have a dataset containing data of convictions. This dataset contains 4
columns:
- personId: individual number that identifies the offender
- law: law which has been violated
- article: article which has been violated

# Testdata:
personId<-c(1,1,2,2,2,2,2,3,4,4)
law<-c("SVG", "SVG", "StGB", "StGB", "SVG", "AuG", "StGB", "SVG", "StGB",
"AuG")
article<-c(10, 10, 123, 122, 10, 40, 126, 10, 111, 40)
testdata<-data.frame(personId, law, article)

Now I'd like to create three additional dummy-coded columns for each law
(SVG, StGB, AuG).
For each offender (all offenders have the same personId) it should be
checked, whether there are
any violations against the three laws. If there are any violations against
SVG (for example), then
in all rows of this offender the column SVG should have the value 1
(otherwise 0).

For example offender 2 has once violated against law "SVG" therefore his
four entries should have
the value 1 at the column "SVG".

I hope you can understand my problem. I'd really appreciate any hints and
solutions!

Thank you!
David

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