On Jun 11, 2009, at 12:13 PM, Mark Na wrote:
Hi R-helpers,
I have the following (dummy) dataframe:
test
DATE LOCATION KIND CLASS COUNT
1 1 1 CAR A 2
2 1 1 TRUCK D 3
3 1 1 BUS E 4
4 1 2 CAR E 2
5 1 2 TRUCK A 7
6 1 2 BUS F 1
That I would like to turn into this:
test2
DATE LOCATION KIND CLASS
1 1 1 CAR A
2 1 1 CAR A
3 1 1 TRUCK D
4 1 1 TRUCK D
5 1 1 TRUCK D
6 1 1 BUS E
7 1 1 BUS E
8 1 1 BUS E
9 1 1 BUS E
10 1 2 CAR E
11 1 2 CAR E
12 1 2 TRUCK A
13 1 2 TRUCK A
14 1 2 TRUCK A
15 1 2 TRUCK A
16 1 2 TRUCK A
17 1 2 TRUCK A
18 1 2 TRUCK A
19 1 2 BUS F
So, basically it's a case of expanding (adding rows to) the first
dataframe
by the value in the COUNT column.
I have solved this problem with the following code:
test2<-with(test, data.frame(DATE=rep(DATE,COUNT),
LOCATION=rep(LOCATION,COUNT), KIND=rep(KIND,COUNT),
CLASS=rep(CLASS,COUNT)))
but I'm unsatisfied with that solution because it's verbose and I
think
there must a more elegant way. If I had more variables than 4 (which
I do in
my real data) it would be a nuisance to repeat each column within
the rep
function.
I would prefer to do this with Base R or package(reshape) than
relying on
another package.
Any ideas? Thanks!
Mark Na
Mark,
A quick and dirty solution:
> test[rep(1:nrow(test), test$COUNT), -ncol(test)]
DATE LOCATION KIND CLASS
1 1 1 CAR A
1.1 1 1 CAR A
2 1 1 TRUCK D
2.1 1 1 TRUCK D
2.2 1 1 TRUCK D
3 1 1 BUS E
3.1 1 1 BUS E
3.2 1 1 BUS E
3.3 1 1 BUS E
4 1 2 CAR E
4.1 1 2 CAR E
5 1 2 TRUCK A
5.1 1 2 TRUCK A
5.2 1 2 TRUCK A
5.3 1 2 TRUCK A
5.4 1 2 TRUCK A
5.5 1 2 TRUCK A
5.6 1 2 TRUCK A
6 1 2 BUS F
For a more general solution to taking a tabulated data frame and
converting it back to the raw data see my expand.dft() function:
https://stat.ethz.ch/pipermail/r-help/2009-January/185561.html
For example:
> expand.dft(test, freq = "COUNT")
DATE LOCATION KIND CLASS
1 1 1 CAR A
2 1 1 CAR A
3 1 1 TRUCK D
4 1 1 TRUCK D
5 1 1 TRUCK D
6 1 1 BUS E
7 1 1 BUS E
8 1 1 BUS E
9 1 1 BUS E
10 1 2 CAR E
11 1 2 CAR E
12 1 2 TRUCK A
13 1 2 TRUCK A
14 1 2 TRUCK A
15 1 2 TRUCK A
16 1 2 TRUCK A
17 1 2 TRUCK A
18 1 2 TRUCK A
19 1 2 BUS F
HTH,
Marc Schwartz
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